Invited talks
I01] Robert de Rosa – Direct Imaging of Exoplanets: From the past to the future
The direct detection of extrasolar planets offers the exciting prospect of a second ”pale blue dot”: images of an Earth-like planet around another Sun-like star. While this may seem like a distant prospect, the work ongoing today, in terms of both the development of instrumentation and the interpretation of observations taken with them, can be viewed with this objective in mind. In this talk I intend to review some of the key developments and discoveries that we have made as a field so far along this journey, in particular highlighting recent results enabled by the latest generation of instrumentation. I will conclude with what we have in store in the near and medium-term, from synergies with other detection techniques, to imaging terrestrial planets with future generations of ground and space-based instrumentation.
I02] Sarah Kendrew – Exoplanet science with the James Webb Space Telescope
The newly launched James Webb Space Telescope looks set to revolutionize our view of the Universe in the infrared. Its 4 instruments offer unprecedented sensitivity and image quality in a variety of imaging, and spectroscopic modes from 0.6 to 28 microns. A significant fraction of JWST’s time in cycle 1 is focused on the detection and characterization of exoplanets and disks. I will give an overview of the prime observing modes for exoplanet science with JWST, their expected performance and some of the first science we expect to see in this exciting area of research.
I03] Grant Kennedy – Circumstellar and Circumplanetary Disks
The gas-rich protoplanetary disks around other stars are where planets form, and the gas-poor debris disks provide part of the environment in which these planets live out their lives. It is probable that many planets themselves host disks of one kind or another at some point, whether this be a building site for satellites at early times or a collection of small bodies and associated dust later on. In this talk I will aim to cover some of the history and background of disk science, with an emphasis on how high-contrast imaging fits within the broader observational context.
I04] Faustine Cantalloube – Algorithms for High Contrast Imaging
High contrast imaging is one of the most sensitive imaging technique to date. It requires dedicated instruments that equip the biggest optical telescopes on Earth, and includes the most performant adaptive optics systems coupled with advanced coronagraphic techniques, all in a stable environment. Since we are looking for circumstellar signals that are a thousand to a million times fainter than the host star, even slight optical aberration or atmospheric residual diffracts starlight in the image plane, unblocked by the coronagraph, and significantly affect the high contrast capabilities of the instrument. To further carve out the bright starlight residuals, tailored post-processing techniques are an essential tool that allows us to gain about one order of magnitude in contrast. During this talk, there will be an overview of existing post-processing techniques: what concept they are based on and what are the intrinsic limitations we are facing today.
I05] Lucie Leboulleux – Socio-demographic study of the high-contrast imaging community
In astronomy, specific groups remain under-represented despite multiple studies that investigate this issue and propose solutions. In particular, gender-based discriminations have been identified at different scales (general astronomy, conferences, labs…) and different subjects (access to permanent positions, PI-ship on projects, conference talks…). At the last Spirit of Lyot conference, held in 2019 in Tokyo (Japan), we conducted a survey to probe the demographics and social behavior of the high-contrast imaging community. We collected data on visibility, self-censorship, inappropriate behaviors, etc. and analyzed it under the prisms of gender and seniority representation (PhD candidate, post-doctoral researcher, permanent researcher). The proportion of women and of non-binary people reveals a more diverse community in comparison to other scientific groups (e.g. the IAU members), but still far from a balanced representation of all genders. Early-career researchers have a lower visibility than permanent researchers, with PhD candidates being under-represented at international conferences, and postdocs being excluded from Science Organizing Committees. Regarding social relations, the results are alarming, in particular when it comes to self-censoring of women or to unprofessional behavior, which was experienced by 54% of this community, mainly by women. The 2019 survey led to a new poll related to the 2022 conference, with the objective of monitoring the evolution of demographics and of social behaviors over time. This 2022 survey has been updated to avoid biases and included in the registration process to encourage participation. In this presentation, we propose to present our study and results to the Spirit of Lyot attendees
I06] Marta Bryan – Characterizing Gas Giants Using High-Resolution Spectroscopy
Over the past few decades thousands of planets with an extraordinary diversity of properties have been discovered.Understanding what physical mechanisms produce these systems has been one of the driving questions in the field.One of the most effective strategies to learn about the formation and evolutionary histories of planets is to characterize them with high-resolution spectroscopy.In this talk I will describe how targeting planet populations at the extremes and leveraging high spectral resolution enables planetary light to be disentangled from its host star.Focusing on hot Jupiters, I will discuss how detection of molecules and metals, atmospheric retrievals and abundance measurements, characterization of winds, and constraints on chemical gradients point to the chemical and physical mechanisms operating in their atmospheres.Moving on to directly imaged planets, I will talk about how retrieved abundances of molecules and isotopologue ratios, rotation rates, planetary obliquities, and doppler imaged maps shed new light on their origins.
Contributed talks
T01] Maissa Salama – Large Adaptive Optics Survey for Substellar Objects (LASSO) Around Young Nearby Low-Mass Stars
The occurrence rates and population trends of massive substellar companions (giant planets and brown dwarfs, 2-70 MJup) at wide separations (>50 AU) from their host star are critical to furthering our understanding of their origins and evolution. However, these objects are very rare and building up a large sample for population-level studies has been challenging. We present results from the continuation of the Large Adaptive optics Survey for Substellar Objects (LASSO) at wide separations around young (<300 Myrs), nearby (<100 pc), low-mass ( 0.1-0.8 MSun) stars. We directly imaged nearly 900 stars. In addition to the previously published 427 stars observed with the robotic laser guide star instrument Robo-AO successively mounted on the Kitt Peak 2.1-m and the Maunakea UH 2.2-m telescopes, we report here on the results from K-band observations with IRCS on Subaru and NIRC2 on Keck of 470 low-mass stars. We selected these stars on the basis of confidence in their youth as likely members of young moving groups, including a set in the young Sco-Cen association, or with measured proper motion accelerations, indicating the likely presence of a companion. We detected 129 companion candidates. The majority of confirmed and pending candidates are stellar companions, with 5 potentially new substellar companions that will require follow-up observations to confirm. These large survey results allow us to better understand the different formation pathways by studying the full range of substellar to stellar companions on a population level.
T02] Markus Janson – Hear ye! Tidings of the BEAST
A fundamental path toward understanding planet formation is to study its outcomes in extreme environments. The B-star Exoplanet Abundance Study (BEAST) is a high-contrast imaging survey with SPHERE at the VLT, which aims to provide the first comprehensive view of planet frequency and demographics around the most massive stars in the Solar neighbourhood. The survey targets 85 B-type stars in Scorpius-Centaurus, and is currently early in the 2nd epoch phase, where candidates are being followed up to check for common proper motion. Here, we will present the BEAST survey and its results so far, which include the discovery of an 11 Mjup planet around the most massive stellar host (6-10 Msun) known. The mass ratio of the system is similar to the Sun-Jupiter system, but with a 100 times wider orbit. These results put considerable tension on conventional planet formation models, and show that planets can form in systems with much higher masses than implied from radial velocity surveys of planets in smaller orbits.
T03] Thayne Currie (Julien Lozi) – The SCExAO Direct Imaging Search for Planets Around Accelerating Stars
We present results from a new exoplanet search combining 1) direct imaging with SCExAO/CHARIS and 2) astrometry from the Gaia and Hipparcos satellites. Our survey targets young stars showing evidence for an astrometric acceleration plausibly due to a planet or brown dwarf companion. CHARIS spectra constrain companion atmospheric properties. Relative astrometry of companions from SCExAO/CHARIS and absolute astrometry of the star from Hipparcos and Gaia together yield direct dynamical mass constraints, circumventing usual challenges in inferring the masses of imaged planets from luminosity evolution models.
Our survey has now produced the first-ever joint discovery of an exoplanet with direct imaging & astrometry and the first utilizing Gaia data. We describe this and other discoveries and how companions we find are crucial benchmarks for understanding planet/brown dwarf atmosphere evolution. Our nascent survey yields a higher detection rate than large blind surveys from GPI and SPHERE and prefigures future campaigns to identify, confirm, and characterize exo-Earths from a combination of direct imaging and indirect methods.
T04] Sylvestre Lacour – Spectrum, astrometry, and new detections: a trove of possibilities offered by optical interferometry
Optical interferometry is now entering a golden age for observing and characterising exoplanets. Its unrivalled angular resolution gives a smaller internal working angle and a better abilities to eliminate speckle noise. This explains why it can directly observe exoplanets very close to their star, undetected by other techniques. During this presentation, I will give an overview of the many results obtained so far within the framework of the ExoGRAVITY project : new direct detection of exoplanets (including beta pictoris c), the use of the CO bandhead at 2.3 micron to constrain formation scenarios, the first attempt to resolve the close environment of the protoplanets PDS70b and c, the various clues offered by ultra-precise astrometry to estimate dynamical masses, and maybe more if I have time!
T05] Carl-Henrik Dahlqvist – The SHARDDS Survey: Limits on Planet Occurrence Rates Based on Point Sources Analysis via the Auto-RSM Framework
In the past decade, HCI surveys provided new insights about the frequency and properties of substellar companions at separation larger than 5 au. In this context, our study aims to detect and characterise potential exoplanets and brown dwarfs within debris disks, by considering the SHARDDS survey, which gathers 55 Main Sequence stars with known bright debris disk. We rely on the AutoRSM framework to perform an in-depth analysis of the targets, via the computation of detection maps and contrast curves. A clustering approach is used to divide the set of targets in multiple subsets, in order to reduce the computation time by estimating a single optimal parametrisation for each considered subset. The use of Auto-RSM allows to reach high contrast at short separations, with a median contrast of 10-5 at 300 mas, for a completeness level of 95%. Detection maps generated with different approaches are used along with contrast curves, to identify potential planetary companions. A new planetary characterisation algorithm, based on the RSM framework, is developed and tested successfully, showing a higher astrometric and photometric precision for faint sources compared to standard approaches. A correlation study between achievable contrasts and parameters characterising HCI sequences highlights the importance of the strehl, wind speed and wind driven halo to define the quality of high contrast images. Finally, planet detection and occurrence frequency maps are generated and show, for the SHARDDS survey, a high detection rate between 10 and 100 au for substellar companions with mass >10MJ.
T06] Mathilde Malin – Atmospheric characterization of exoplanets with the medium resolution spectrometer on MIRI/JWST
Direct observations are required to constrain the physical properties of exoplanet atmospheres. Direct imaging is still challenging as it requires to achieve very high contrasts at small separations. The current generation of ground based instruments are reaching contrast performance that allows us to observe young and warm giant planets that are separated by a few AU from their host star, a favorable configuration to mitigate the diffracted starlight contamination. The Mid-IR Instrument (MIRI) of the recently launched James Webb Space Telescope is equipped with a Medium Resolution Spectrograph (MRS) covering a large spectral range from 5 to 28 microns. At such wavelengths, the star to planet flux ratio is more favorable than in the near IR and provides access to molecular signatures that are relevant to characterize exoplanet atmospheres at a spectral resolution as large as 3700. We are investigating the feasibility to retrieve those molecules with the method called the molecular mapping which allows to disentangle spectrally and spatially the light from the star and the planet. We will present results of performance estimation based on simulations of MIRI observations. Simulating many known direct imaged systems, we detect and retrieve molecules such as CO, CH4, NH3, H2O, PH3, HCN and using a large grid of Exo-REM atmospheric models, we are exploring the sensitivity of the method to determine atmospheric parameters. Finally, we will present a parametric analysis of MIRI/MRS detection capacity, studying the impact of the spectral type and the angular separation on the methods performance. Once combined with near IR data or coronographic data, MIRI-MRS will have the capacity to improve the characterization of exoplanetary atmospheres and to derive constraints on planetary formation.
T07] Sasha Hinkley (Elisabeth Matthews) – High Contrast Imaging of Exoplanets and Exoplanetary Systems with JWST
The JWST Early Release Science (ERS) Program will be our first opportunity to directly characterize exoplanets over their full luminous range. Our accepted 54-hour JWST ERS program will directly characterize two recently-discovered, directly imaged planetary mass companions over their full spectral range from 2- 28 microns using photometry and spectroscopy. Ours will be among the first-ever observations of bona fide exoplanets at these wavelengths, and will be crucial test cases for atmospheric models that have mostly focussed in the visible and near-infrared. Further, our program will demonstrate the degree to which atmospheric abundance analysis can be obtained from JWST spectroscopy, possibly providing clues to the planet formation process. Within the first few months of JWST operation, our program will rapidly produce publicly- available datasets in modes to be commonly used by the exoplanet direct imaging communities. In addition, I will describe how our international team of investigators will deliver science enabling products to empower a broad user base to develop successful future JWST investigations dedicated to direct-imaging surveys for low-mass exoplanets (e.g. Saturn mass) in Cycle 2 and beyond.
T08] Tim Pearce – The outer-planet population inferred from a large sample of debris discs
We know little about the outermost exoplanets in planetary systems, because current detection methods are insensitive to moderate-mass planets on wide orbits. However, insight can be gained by using debris discs as indirect planetary probes. I present the results of a large study inferring the outer-planet population from 178 debris-disc systems, using several dynamical arguments including that unseen planets sculpt and/or stir debris. We reach a range of conclusions, including that the population of planets perturbing debris discs at late times is remarkably similar to the population inferred to be forming in protoplanetary discs at early times; these could be the same population if newly formed planets do not migrate as far as currently thought. We demonstrate that ‘typical’ cold debris discs likely require Neptune- to Saturn-mass planets at 10-100 au, with some needing Jupiter-mass perturbers; these planets are currently undetectable, but modest detection-limit improvements (e.g. from JWST) should reveal many of them. Therefore, having long predicted unseen planets from debris disc features, we may finally be approaching the era where such models can be directly tested via planet detections. Finally, we use a new analysis to show that some debris discs cannot be self-stirred unless their size distribution is very different to that conventionally assumed, further hinting at the need for stirring planets in some systems. Our study provides planet predictions for all 178 systems, some of which form the basis of several JWST Cycle 1 programmes.
T09] Evan Rich – Gemini-LIGHTS: a survey of Herbig Ae/Be and massive T-Tauri protoplanetary disks imaged with Gemini Planet Imager
We present a sample of 44 protoplanetary disks from the Gemini- Large Imaging with Gpi Herbig/Ttauri Survey (Gemini-LIGHTS), which observed bright Herbig Ae/Be stars and T-Tauri stars to search for signatures of disk evolution and evidence of ongoing planet formation. We utilized high-contrast polarized imagery in J- and H-bands with the Gemini Planet Imager (GPI) at the Gemini South Observatory. Targets in the sample were selected based on their near- and mid-infrared colors selecting a less-biased number of transitional, pre-transitional, and full disks. We detect scattered light signatures around 75% of our 44 targets. We also detected point-like companions for 47% of the targets within the 2” field of view, including 1 super-Jupiter mass candidate and 4 brown dwarf candidates. We searched for correlations between the polarized flux with system parameters, finding a few clear trends: far-IR excess in the SED correlates with polarized flux, presence of a companion star drastically reduces the scattered light levels, and systems hosting disks with ring structures have star masses less than 3 solar masses. Our sample also included four hot, dusty ”FS CMa” systems and we detected large-scale (>100 au) scattered light around each, signs of extreme youth for these enigmatic systems. Data from this survey is publicly available using a new FITS file standard jointly developed with members of the VLT/SPHERE team.
T10] Schuyler Wolff – Digging Deep with HST+JWST on Archetypal debris disks; Epsilon Eridani, Fomalhaut and Vega
We present a joint HST+JWST coronagraphic study of the three nearest and preeminent debris disk systems: Epsilon Eridani, Fomalhaut, and Vega. These archetypal systems have robust fractional infrared luminosities with asteroid belt analogues (inferred from spectral energy distributions) and host complex circumstellar environments. Epsilon Eridani boasts at least one Jupiter-like exoplanet and three debris belts, Fomalhaut hosts a Kuiper belt analogue and a contentious planet, and Vega contains two debris belts and a tentative radial-velocity planet. Through three legacy HST programs, we have achieved the deepest HST/STIS contrasts of the intermediate and outer disk regions to search for the influence of unseen planets and constraint dust properties. We illustrate our approach with Epsilon Eridani where we have generated a theoretical dynamical model to predict the architecture of the debris system consistent with the inner planet and a putative outer one, and used this prediction to match both the thermal infrared and new HST ultra-deep coronagraphic data. These sources are also the target of a MIRI GTO program to resolve the inner, asteroid belt analogues for these systems. The superb angular resolution provided by the MIRI 4QPM is uniquely capable of imaging these debris disks at the locations of important ice lines. We aim to determine if these asteroid belts are formed from evaporation of comets at the current ice-lines or if these are the remnants of fossil planetesimal belts. We will also detail JWST coronographic data analysis tools advantageous to future GO programs.
T11] Nick Oberg – Circumplanetary Disks in the Mid-Infrared with METIS
Transitional disks around young stars with large inner dust cavities are promising targets to search for newly formed giant planets. Massive embedded planets are expected to accrete gas and dust from the surrounding circumstellar disk into a circumplanetary disk (CPD) in which regular satellites can form. While continuum observations have had spectacular success in detecting circumplanetary dust (in e.g. the PDS 70 system), complementary spectral line observations are needed to fully characterize a CPD. High spectral resolution observations in the Mid-IR allows us to probe the molecular emission lines (H2O, CO, CO2, OH, HCN, C2H2) from the gas in CPDs. Optically thin lines of molecular isotopologues enable measurement of the total gas mass. Line morphology allows us to directly estimate the planet mass and degree of gas orbital deviation from Keplerian motion; key to understanding dust dynamics of fundamental importance of the moon formation process. Such observations can thus reveal the properties of the planet as well as details of the latter stages of gas giant accretion and the moon formation process. The small angular separation of these objects from their host stars and relatively weak flux compared to the hot inner rims of disk cavities has made direct detection challenging. We perform simulations to demonstrate the METIS instrument on the ELT will allow us to resolve the planet/CPD from the host star, and that high spectral resolution IF spectroscopy in the L and M band will enable an unprecedented view into these diminutive accretion disks.
T12] Hans Martin Schmid – Quantitative polarimetry of circumstellar dust with high contrast observations
Differential polarimetric imaging is a powerful high contrast technique for the detection of the scattering dust in circumstellar disks and stellar winds. However, the detailed characterization of the circumstellar dust requires quantitative measurements of the intensity, and the polarized intensity of the scattered light for different wavelength bands. This is very challenging for high contrast observations using AO instruments because of the variable PSF and the instrumental polarization effects. I describe and discuss in this contribution the required calibration steps for quantitative polarimetric measurements of faint circumstellar dust emission and present recent results on derived dust scattering parameters.
T13] Ryo Tazaki – Characterization of complex-shaped dust aggregates in planet-forming disks by optical and near-infrared observations
Collisional growth of dust aggregates is the first step of planet formation. In particular, the size of the constituent particles (monomer) and structure of dust aggregates have been suggested to play an essential role in collisional growth. However, these detailed dust properties have not yet been well constrained from disk observations. To better characterize the aggregate properties from disk observations, we have performed a comprehensive parameter survey on light scattering properties of complex-shaped dust aggregates, using an exact numerical method called the T-matrix method. The results were then compared with the optical and near-infrared (IR) observations of planet-forming disks. In this talk, I will highlight three major results. First of all, we show that the monomer size of dust aggregates is likely sub-micron-sized, which is favorable for efficient collisional dust growth in disks. Second, we show that the polarization scattering phase functions of the IM Lup disk can be naturally explained by the presence of micron-sized fractal aggregates. Finally, we develop a simple, physically motivated, analytical model for describing a scattering phase function of fractal aggregates. The simple model would be useful in the context of not only planet-forming disks but also exoplanetary hazy/cloudy atmospheres. Combining the above findings, we conclude that optical and near-IR polarimetric observations of disks are crucial for characterizing early planet formation.
T14] Sarah Betti – Detection of Near-infrared Water Ice at the Surface of the (Pre)Transitional Disk of AB Aur
One important key to interpreting observational signatures of planet formation is understanding the role icy grains play in the formation process, as icy grains aid grain coagulation and planetesimal growth, making them an important component of giant planet formation. Transition disks, likely sites of ongoing planet formation, are ideal laboratories to search for these icy grains. We use LBT/LMIRCam data to map the transitional disk around the young ( 4Myr) Herbig Ae/Be star AB Aur at the 3.09m ice feature. This, together with observations at bracketing wavelengths (Ks and L), allows us to probe the location(s) of volatile reservoirs needed to build giant planet cores, as well as compositional gradients in the disk. We find strong morphological differences between the bands, including asymmetries consistent with previously observed spiral arm structures. An apparent scattered light deficit at 3.08m relative to the bracketing wavelengths is evocative of disk surface ice absorption, but the (KsH2O) color is consistent with grains with little ice (0%5% by mass). We find that the extremely red (KsL) disk color cannot be reproduced under conventional scattered light modeling with any combination of grain parameters or reasonable local extinction values. We hypothesize that the scattering surfaces at the three wavelengths are not colocated, and the optical depth effects result in probing grain populations at different disk surface depths. These results suggest that while the disk surface is highly ice-poor, further investigation is necessary to understand the optical depth effect between NIR wavelengths.
T15] Christian Ginski – SPHERE-DESTINYS: Imaging the cradles of planet formation
In the past decades several thousand extrasolar planets have been discovered around stars in the Galaxy. These planets span a diverse range of masses and orbital periods. Strikingly they are all different from the planets in our own solar system. To understand the different formation pathways we have to go back to the beginning and study the initial conditions of planet formation. I will discuss the DESTINYS (Disk Evolution Study Through Imaging of Nearby Young Stars) survey, undertaken with the SPHERE extreme adaptive optics imager at the ESO VLT. Within DESTINYS we systematically observe the circumstellar environment of members of nearby young star forming regions in polarized scattered light on resolved scales of 10 au. In this way we can trace the disk evolution as well as sub-structures, thought to be introduced by planet-disk interaction, within the first 10 Myr, i.e. the key formation phase of planets. I will present recent observational results of this ongoing survey program and in particular discuss how they complement observations by other facilities and at different wavelengths.
T16] Katie Crotts – A Multi-Wavelength Study of the Extreme Debris Disk Around HD 111520
We observed the nearly edge-on debris disk system HD 111520 at J, H, & K1 near-IR bands using both the spectral and polarization modes of the Gemini Planet Imager (GPI). With these new observations, we have performed an empirical analysis in order to better understand the disk morphology and its highly asymmetrical nature. We find that the disk’s large brightness asymmetry between the two disk extensions is greatest in the J band, in both polarized and total intensity observations (1.8:1 compared to 1.5:1). We also find that the radial location of the peak polarized intensity differs on either side of the star by 11 AU, suggesting that the disk may be eccentric. However, such an eccentricity would not be able to fully explain the large brightness asymmetry observed. Measuring the disk color shows that the brighter extension is relatively bluer in J-H and J-K1 compared to the dimmer extension, suggesting that the two sides may have different dust grain properties. In all, these findings are consistent with the hypothesis that a recent collision occurred between two large bodies in the northern extension of the disk, although confirming this based on near-IR observations alone is not feasible. Follow-up imaging with ALMA to resolve the asymmetry in the dust mass distribution is essential in order to better constrain the dust properties on either side of the disk.
T17] Gabriele Cugno – Revealing the population of forming giant planets
Two main families of models (cold-start and hot-start models) describe the formation process of gas giants, differing primarily in the amount of entropy retained by the planet at the end of its formation. This is a key quantity impacting other parameters like temperature and radius. After 100 Myr these parameters converge and it is no longer possible to reconstruct the formation history of planets. Hence, it is crucial to identify and characterize young companions in the first phase of their life. Since 2016, the NaCo-ISPY large program collected deep high-contrast imaging data of 50 young protoplanetary disks in the L band, making it the largest existing survey uniquely focused on this type of objects. The main goal of the survey is to search for (forming) gas giant planets around disk-hosting stars, with the main intent of statistically characterise their population. In this contribution, I will present newest results from the ISPY protoplanetary disks survey. I will reveal the detection of known and new planetary and binary systems, and I will present reliable detection limits obtained using a novel approach that ensures a rigorous statistical treatment of the noise at small separations. After considering absorbing effects of the disk, those limits were translated into detection probability maps, providing strong constraints on which planet architectures could exist and on the overall giant planet population around young stars. Overall, the NaCo-ISPY results provide a unique opportunity to test and evaluate the existing planet formation theories.
T18] Nienke van der Marel – The impact of icy dust transport and dust traps on exoplanet atmospheres
The chemical content of a planet-forming disk sets the atmospheric composition of the planets that have formed within it. The inheritance of ices from the dark cloud phase and the transport of these ices through the disk as the result of radial drift and trapping of large dust grains may be much more important for the distribution of molecules throughout the disk than previously thought, especially at the gap edges where material is directly accreted onto the forming planets. Recent observational work has shown that complex organic molecules (products of ice chemistry) are in some disks cospatial with dust traps, while in others they appear not to be. Furthermore, the elemental C/O ratio varies from disk to disk. Both of these diversities can be understood by considering the effects of icy dust transport. In this talk I will present the most recent developments in the analysis of chemical complexity as the result of transport of icy pebbles, through a number of new ALMA observations. I will discuss the implications for the disk chemistry, the impact on exoplanet atmospheres, and the interpretation of atmospheric measurements that are expected to arrive with JWST and ARIEL in the near future.
T19] Dorian Demars – Emission line variability of young accreting planet and brown dwarf companions
Emission lines at optical and NIR wavelengths indicative of active accretion have been evidenced on 11 protoplanets and low-mass brown-dwarf companions (M<30MJup). Line variability is common in pre-main sequence stars. It has been fortuitously evidenced on a handful of low-mass companions but has never been characterized in detail. Variability can help clarify the accretion mechanisms at play and revise current protoplanet detection strategies. We present the result of a monitoring campaign of the Paschen Beta emission lines (1.28m) of accreting 10-30MJup companions with the VLT/SINFONI integral field spectrograph. We probe and evidence significant variability on minutes to years timescales with radically different behaviors from one object to another. We also report the detection of emission lines on a new low-mass brown-dwarf companion. The timescale and amplitude of the variability are compared to predictions from accretion models to discuss the underlying mechanisms at play. We also discuss the implications of our findings for the detection of protoplanets based on their line emissions (e.g., PDS70b and c, etc) with operating (MUSE, MagAO-X, SPHERE) and upcoming instruments (ERIS, MAVIS, HARMONI).
T20] Gabriel-Dominique Marleau – Accreting protoplanets: Spectral signatures and extinction of gas and dust extinction at H α
Accreting planetary-mass objects have been detected at H alpha, but targeted searches have mainly resulted in non-detections. Emission lines should originate from the accretion shock, making them susceptible to extinction by the accreting material. In the near future, high-resolution (R>50,000) spectrographs operating at H alpha should enable the study of how the incoming material shapes the line profile. In this contribution, we report the results from radiative transfer calculations of the H alpha line for three simplified accretion geometries: spherical symmetry, polar inflow, and magnetospheric accretion. We focus on (i) how much the gas and dust accreting onto a planet reduce the line flux from the shock and (ii) how they affect the line shape. We found that at low accretion rates (Mdot < 3 × 10−6 MJ/yr), gas extinction is essentially negligible and at most a few magnitudes at higher Mdot. For most parameter combinations, extinction by the accreting matter should be negligible, simplifying the interpretation of observations. However, extinction flattens the LHa–Mdot relationship, which gets a maximum luminosity LHa 1 × 10−4 LSun towards Mdot 1 × 10−4 MJ/yr for a planet mass 10 MJ. At high Mdot, strong absorption reduces the H alpha flux, and some measurements can be interpreted as two Mdot values. Finally, we show how highly resolved line profiles (R 1 × 105) can provide (complex) constraints on the thermal and dynamical structure of the accretion flow, helping to reveal by what mechanisms protoplanets accrete.
T21] Stefan Kraus – Exoplanet Spectroscopy and Planetary System Architectures with the VLTI/BIFROST instrument
We present the exoplanet science case for the VLTI/BIFROST instrument. This instrument recently received funding from the European Research Council and aims for first light on Paranal in late 2024 as part of the Asgard Suite of VLTI visitor instruments. BIFROST will be the first VLTI instrument optimised for short wavelengths (1-1.6 micrometer) and high spectral resolution (up to R=25,000). This will allow us to measure the alignment between the stellar spin axis and the planetary orbital axis even for wide-separation systems where this information is inaccessible with other techniques, such as the Rossiter McLaughin effect. We will use these unique constraints to study the dynamical processes that shape system architectures, over the whole mass range from stellar-mass companions down to planets. Furthermore, BIFROST will enable the atmospheric characterisation of cold giant planets that are due to be discovered with direct imaging or GAIA astrometry. GRAVITY has demonstrated that the star-light suppression from adaptive optics can be combined with star-light suppression from interferometry by placing the instrument fiber off-axis and adjusting the optical path delay to record at the predicted delay position of the planet. BIFROST will employ this method in J and H-band, providing access to additional molecular tracers, such as the O2 absorption bands. These tracers are highly complementary to the K-band probed by GRAVITY and provide further constraints for atmospheric retrieval. Due to the small inner working angle of about 0.025””, BIFROST also offers the best chance in near future for performing spectroscopy on rocky planets in the terrestrial zone, such Proxima Centauri b.
T22] Carles Cantero – Using local noise statistics to improve the supervised learning of exoplanets detection
Most of the state-of-the-art HCI algorithms rely on PSF subtraction techniques to produce the so-called processed frame, where the exoplanet detection is performed. The bulk of these algorithms assume that, thanks to PSF subtraction and to the derotation and averaging of multiple frames, residual noise in the processed frame can be modeled as Gaussian. However, it has been shown that the Gaussian assumption leads to high false positive detection rates especially for small angular separations, where speckles are not perfectly removed and still dominate over other kinds of noise. The understanding and modeling of residual noise plays a crucial role in detection tasks. Therefore, motivated by this, we first perform a statistical study that allows to represent the residual noise on processed frames with the aim of improving detection rates. Afterwards, we build Annular-SODINN, a new supervised ML detection algorithm that is able to disentangle companion signatures from speckles. In comparison with its predecessor, aSODINN takes advantage of two additional information sources that improve the training: (i) Our study of the residual noise allows to split the FoV in noise regimes in such a way a different model can be trained on them and capture better noise dependencies. (ii) Additionally, we feed the training with SNR curves and number of principal components in the PCA-ADI processing, after injecting fake companions. Finally, we test aSODINN on the recent Exoplanet Imaging Data Challenge and show that it performs better detection rates than its predecessor and most of the state of-the-art detection algorithms.
T23] Kate Follette – Robust Detection and Interpretation of Accreting Protoplanet Signals
Accreting protoplanets offer an unprecedented window into substellar formation pathways and planetary accretion physics. However, the determination of accurate protoplanet accretion rates suffers from several complicating factors. First, protoplanets are embedded in complex circumstellar disks, and disentangling planetary and disk emission is a difficult and controversial process. Robust, data-driven, and well-validated techniques are a pressing need in the direct imaging community. I will discuss the work of my group to develop high-fidelity extraction methods for planetary accretion signals in H-alpha differential images. These new approaches have led to quantitative improvements in the recovery of known accreting companions and the detections of two new accreting protoplanet candidates. I will also discuss our work to inform a second known issue in the interpretation of exoplanet accretion signatures: that current planetary accretion rate estimates assume a likely incorrect equivalence between stellar and planetary accretion physics. Our group has assembled a comprehensive database of substellar accretion rates for all known brown dwarfs and exoplanets in the literature, and we use a combination of this empirical sample and new simulation tools to understand the origins (physical and observational) of the large observed scatter in the object mass to mass accretion rate relation. I will also describe preliminary results from several observational campaigns to probe the validity of empirical scaling relations between objects accretion line luminosities and their mass accretion rates in the substellar regime. Together, these datasets and computational tools are helping us to better understand how to robustly isolate and accurately interpret protoplanetary accretion signatures.
T24] Markus Johannes Bonse – Comparing Apples with Apples: Statistically sound Detection Limits for Exoplanet High Contrast Imaging
Over the past decade, hundreds of nights have been spent on the worlds largest telescopes to search for and directly detect new exoplanets using high-contrast imaging (HCI). Thereby, two scientific goals are of central interest: First, to study the characteristics of the underlying planet population and distinguish between different planet formation and evolution theories. Second, to find and characterize planets in our immediate Solar neighborhood. Both questions heavily rely on the metric used to calculate the achieved contrast. Currently used standards often rely on several explicit or implicit assumptions about the noise. While being an inseparable part of the metric, these assumptions are rarely verified. This is problematic as any violation of these assumptions can lead to systematic biases. The severity of the bias depends on the extent to which the assumptions are violated. This makes it hard, if not impossible, to compare results across datasets or instruments with different noise characteristics. In this contribution, we revisit the fundamental question of how to quantify detection limits in HCI. We focus our analysis on the error budget resulting from violated assumptions. For this purpose, we propose a new metric based on bootstrapping which generalizes current standards to non-gaussian noise. We apply our method to archival HCI data from the VLT and derive detection limits for different types of noise. Our analysis shows that current standards tend to overestimate the achieved detection limits by more than one magnitude. That is, we may have excluded planets that can still exist.
T25] Antoine Chomez – IMPROVING DETECTION LIMITS ON DIRECT IMAGING : THE PACO ALGORITHM PERFORMANCES
Direct imaging is nowadays unique to explore the outer part of exoplanetary systems (beyond 10 au), and complement their global exploration in synergy with other techniques like transit, radial velocity, astrometry, and micro-lensing. With the advent of ELTs in the coming decade, imaging and characterizing the bulk of the giant planet population primarily formed through core accretion, and lying beyond the snow line between typically 1 to 10 au will be possible. The development of new advanced signal processing techniques is fundamental in this context to optimally exploit the temporal, spatial and spectral diversity of future instruments. Current planet imagers like SPHERE or GPI already provide exciting results to enter the planet-forming region for very nearby, young stars. I will present the perspectives and results offered by the performance of the PACO algorithm applied to a small sample of 30 close and young solar-type stars which serves as a test-bed for a massive reduction of the SPHERE archive for the search of close-in exoplanets. I will highlight the gain brought by the optimization of the detection capabilities of PACO with the use of spectral priors, as well as improvements on the whole reduction pipeline built on all the experience gained on SPHERE during its 7 years of service. Finally I will present the detection performances (detection limits, companions,…) from this test-survey. This work will pave the way to the massive reduction of the SPHERE archive, led by the SHINE survey.
T26] Bin Ren – Total intensity circumstellar disk imaging from data imputation: towards optimal extraction of disks
After successful disk extraction with polarization differential imaging (PDI), total intensity disk imaging has been the bottleneck of disk studies, which is preventing a good understanding of dust composition and an optimal detection of the thermal emission of protoplanets. This stems from the fact that overfitting has been plaguing data reduction for existing point spread function (PSF) modeling methods. Here we demonstrate the data imputation capability of sequential non-negative matrix factorization (DI-sNMF) using reference differential imaging (RDI) observations. By ignoring the disk-hosting regions in PSF modeling, we apply DI-sNMF to (1) new star hopping observations from VLT/SPHERE on 20 transition disks, (2) complementary archival SPHERE and Keck/NIRC2 data on a subset of these disks, (3) JWST simulations of debris disk observations. We could reach RDI data quality that is on par with PDI for disk images, with RDI further offering the capability of imaging planets embedded in disks. Behind the scenes, the fraction of ignored data in DI-sNMF only contributes to a 4th order term in ideal scenarios, thus minimizing overfitting to an unprecedented level. We will further discuss the science topics that are enabled by RDI data imputation (morphology, polarization fraction, dust color, etc.), as well as moving towards obtaining reflectance spectroscopy for dust composition with SPHERE and GPI, and background removal for extragalactic studies with Keck/KCWI.
T27] Sarah Steiger – The MKID Exoplanet Camera (MEC) for Subaru SCExAO: Using Stochastic Speckle Discrimination for High-Contrast Imaging
The Microwave Kinetic Inductance Detector (MKID) Exoplanet Camera (MEC) is a y-J band integral field unit located behind the Subaru Coronagraphic Extreme Adaptive Optics system (SCExAO) at the Subaru Telescope on Maunakea. The detector inside of MEC is a 20 kilo-pixel photon-counting MKID array that yields not only the energy of each photon (R 5), but also its arrival time (to within a microsecond) with no read noise or dark current. This temporal resolution allows us to perform postprocessing techniques that leverage differences in the photon arrival time statistics between stars and their faint companions such as Stochastic Speckle Discrimination (SSD). With SSD, we have demonstrated the ability to uncover low mass stellar companions and now present the first results of this technique on a diffuse source using MEC observations of the disk around AB Aurigae. Here we can resolve structures in the disk within 0.3 without the use of any PSF subtraction or polarization. This analysis is made possible through the use of The MKID Pipeline, a new open-source data reduction and analysis pipeline developed for MKID instruments that takes raw MKID data as its input and can return not only unique MKID data products for specialized analysis, but also science quality images that can easily interface with existing post-processing techniques (e.g. ADI) for more general science.
T28] Rico Landman – Trade-offs in high-contrast integral field spectroscopy for exoplanet detection and characterisation
Combining high contrast imaging with medium/high resolution integral field spectroscopy has the potential to boost the detection rate of exoplanets and allow for the characterisation of their atmospheres. The achievable spectral resolution, bandwidth and field of view of such an instrument are all limited by the number of available detector pixels. In this talk, I will show the results of a trade-off study between these parameters for the detection and characterisation of exoplanets. We find that T-type companions are most easily detected in J/H band through methane and water features, while L-type companions are best observed in K/H band through water and CO features. We show that molecular absorption spectra generally have decreasing power towards higher spectral resolution and that molecule mapping is already powerful at moderate resolutions (R≳300). Such an instrument does not need to have a large field of view, as most of the gain in contrast is obtained in the speckle limited regime close to the star. Finally, we show that the same trade-offs are also valid for the obtainable constraints on atmospheric parameters such as the C/O ratio, metallicity, surface gravity and temperature.
T29] Nour Skaf – Structures in the Beta Pictoris disk at 12 um with NEAR-VISIR
Beta Pictoris is a young nearby system hosting a well-resolved edge-on disk, as well as at least two exoplanets. It offers key opportunities to better understand planet formation and evolution. In December 2019, we collected 12 um coronagraphic observations of this system with the VISIR-NEAR experiment taking advantage of the adaptive secondary mirror at the VLT, making those data the first high contrast images in the infrared of the system. The main objectives were to attempt to detect the planet and to study disk structure. Although planet b was not detected, the contrast achieved at the planet position was not deep enough to put constraints on atmospheric scenarios. However, we used the upper limit on the 12 um flux to derive constraints on the existence of circumplanetary material. Assuming temperatures and sizes of the dust grains which could reside around the planet between the planet Roche radius and the Hill sphere we infer the corresponding maximum mass of material. We were able to rule out the presence of a Saturn-like ring around the planet. In addition, the disk, uniquely well resolved, presents several noticeable structures, among others the known southwest clump, for which, using three previous epochs of observations at the same wavelength from 2003, 2010, 2015, with the 2019 data, we found its orbit to be Keplerian with a radius of 55.1 to 57.4 AU. This is ruling out this dust clump to be in resonance with an inner or outer planet, as well as the massive collision scenario. Furthermore, we identified another fainter clump at the northeast side of the disk, located at 33.6 AU from the star, and a width of approximately 15 AU. These dust clumps are apparently correlated with the location of the CO clumps detected with ALMA.
T30] Christian Marois – Deployment of focal plane WFS technologies on 8-m telescopes: from the Subaru SPIDERS pathfinder, to the facility-class imaging systems
Facility-class high-contrast exoplanet imaging systems are currently limited by non-common path quasi-static speckles. Due to these aberrations, the raw contrast saturates after a few seconds. Several active wavefront correction techniques have been developed to remove this noise, with limited successes. The NRC Canada is funding two projects, the SPIDERS pathfinder at the Subaru telescope (ETA 2023), and the CAL2 upgrade of the Gemini Planet Imager-2 (ETA 2024), to deploy a modified self-coherent camera (SCC, based on the FAST coronagraph) to measure the focal plane electric field, and to apply wavefront corrections in closed loop down to 10s of ms in a narrow band. The CAL2 project will focus at developing a facility-class focal plane & Lyot-based low-order sensors using a CRED2 and a SAPHIRA-based camera, reaching up to a gain of 100x in contrast for bright stars. The SPIDERS pathfinder will have a similar configuration with the addition of an imaging Fourier Transform spectrograph, allowing the acquisition of a 3.5 diagonal FOV to up to R-20,000 in the NIR to perform advanced spectral differential imaging at high-spectral resolution to search and characterize exoplanets. These projects will serve as the foundation to develop similar systems for future ground-/space-based telescopes, and be an important step toward the development of instruments to search for life signatures in the atmosphere of exoplanets. In this presentation, I will showcase both projects, their scope, their timeline, and simulations of expected performances. I will also showcase NEW EARTH Laboratory results to demonstrate working prototypes.
T31] Kevin Barjot – First light of the upgraded FIRST visible fibered interferometer at the Subaru telescope
FIRSTv2 (Fibered Imager foR a Single Telescope version 2) is the upgrade of a post-AO spectrointerferometer that enables high contrast imaging and spectroscopy at spatial scales below the diffraction limit of a single telescope. FIRST is currently installed, and routinely used on the Subaru telescope as a module of the Subaru Extreme AO (SCExAO) platform. It achieves sensitivity and accuracy by a unique combination of sparse aperture masking, spatial filtering by single-mode fibers and crossdispersion in the visible (600-800nm). The ongoing upgrade aims at using a photonic chip beam combiner consisting of waveguides engraved in a block of glass such that each pair of sub-apertures is combined independently. With one output per baseline, the complex visibility for every baseline is estimated by temporally modulating the phase. Using this integrated optics technology will increase the stability and sensitivity, and thus improve the dynamic range. In this presentation, we will report on the first light of FIRSTv2 equipped with a 5-input chip prototype, at the Subaru Telescope. We will thus show the on-sky results obtained with this photonic device, for the first time in the visible, on unresolved stars (Vega, Spica and RhoPer) and on a binary star (Capella). This is the first step towards the full upgrade of FIRSTv2, that will ultimately provide unique capabilities to detect and characterize close companions such as exoplanets, by combining high angular resolution and spectral resolution in the visible.
T32] Olivier Guyon – High Contrast Imaging at the Photon Noise Limit with WFS-based PSF Calibration
High contrast imaging observations are currently limited by speckle noise due to residual wavefront aberrations. We demonstrate that real-time telemetry from pupil and focal plane WFSs can be used to reliably recover unwanted focal plane speckles, so they can be numerically removed in post-processing. We show that WFS telemetry contains information to compute the distribution of speckles in focal plane images, allowing for reconstruction of speckle noise within each science exposure at the photon noise limit. We describe the conditions under which speckles can be reconstructed from WFS telemetry with high accuracy and precision, and present corresponding algorithmic approaches. We present laboratory and on-sky validation performed with the Subaru Coronagraphic Extreme AO (SCExAO) instrument, establishing an unambiguous relationship between WFS data and speckle noise realization. The mapping from WFS telemetry to speckle noise is first empirically inferred from the dataset, and then used to compute and remove speckle noise from individual short exposure science images. Our results, obtained with both an imaging coronagraph and a nearIR photonic nuller, reveal that speckles are reconstructed to high precision, with speckle-subtracted images dominated by photon noise and essentially free of speckle noise, and a 10x gain in contrast detection limit. We discuss practical implementation, and implications for the design of future high-contrast imaging. We show that the photonic nuller approach which combines nulling and wavefront sensing in the same device is particularly wellsuited in this context, and discuss scientific applications for imaging potentially habitable exoplanets around nearby stars with ground and space telescopes.
T33] Rob van Holstein – Expanding the polarimetric capabilities of SPHERE-IRDIS to uniquely characterize the formation environments of planets
The near-infrared linear-polarimetric imaging mode of SPHERE-IRDIS has proven to be very successful for the detection and characterization of planet-forming disks. In this talk, I will present our efforts to extend the polarimetric capabilities of SPHERE-IRDIS using the existing hardware. By taking advantage of the high polarimetric accuracy of the IRDAP pipeline, we detected for the first time near-infrared linear polarization of several known, directly imaged planetary mass companions. Because these companions have previously measured hydrogen emission lines and red colors, the polarization most likely originates from accretion disks surrounding the companions. We also devised and tested an observing scheme to measure circular polarization with IRDIS. We use the strong polarization crosstalk produced by the image derotator to convert incident circular polarization into measurable linear polarization. With this mode, we aim to measure for the first time circular polarization in planet-forming disks to characterize disk structures, scattering asymmetries, dust properties, and magnetic-field geometries, and to perhaps even shed light on the emergence of homochirality in biomolecules. Finally, we are currently developing a spectropolarimetric mode by combining the IRDIS long-slit spectroscopy (LSS) mode with polarimetry. We aim to use this mode to study the formation of planets and the origin of water on Earth by detecting for the first time water ice at solar-system scales in planet-forming disks, potentially revealing the water-ice sublimation line. Our efforts enable uniquely ways to characterize the formation environments of planets and explore new science cases and techniques for future high-contrast imaging polarimeters such as ELT/PCS.
T34] Sebastiaan Haffert – Observing giant planet accretion kinematics with MagAO-X and the Visible Integral Field spectrograph eXtreme (VIS-X)
Planet formation consists of several steps and processes which are not well understood. It is also not possible to confirm or exclude various proposed mechanism as there are very limited observations of planets during the early stages of planet formation. Hydrogen emission lines provide an exciting window into the accretion of giant planet atmospheres. However, the strongest emission line (on ground-based telescopes) is the Hydrogen-alpha line, which is very blue for current generation of adaptive optics systems and most systems suffer from low Strehl at such wavelengths. MagAO-X system is a new adaptive optics for the Magellan Clay 6.5m telescope. MagAO-X has been designed to provide extreme adaptive optics (ExAO) performance in the visible with Strehl ratios up to 70% at H-alpha. The H-alpha emission line is so narrow that observations in narrowband filters still contain significant photon noise from the stellar continuum. Observing at high-spectral resolution (R>1000) has shown to be very powerful and should be preferred if we aim to measure emission lines. VIS-X is an integralfield spectrograph specifically designed for MagAO-X to do this. VIS-X will cover the optical spectral range (450 to 900 nm) at high-spectral (R=15.000) and high-spatial resolution (7 mas spaxels). The combination of MagAO-X with VIS-X is 100 times more sensitive to accreting protoplanets than any other instrument to date according to end-to-end simulations. VIS-X can also resolve the planetary accretion lines due to its high spectral resolution, and therefore it can start to constrain the kinematics of the accretion process. The instrument is scheduled to have its first light in Spring 2022. We will show and discuss the end-to-end performance and show the first light results.
T35] Steph Sallum (Deno Stelter) – Thermal Infrared Exoplanet Science with SCALES and PSI-Red
The Santa Cruz Array of Lenslets for Exoplanet Spectroscopy (SCALES) passed its Preliminary Design Review in mid-November 2021. SCALES is a 2 – 5 micron coronagraphic high-contrast integral field spectrograph that will be deployed behind the adaptive optics (AO) system of the 10-meter Keck II telescope. It is designed to carry out detailed characterization of exoplanet atmospheres using both low-resolution (R 10-300) and mid-resolution (R 3-7000) integral field spectroscopy over a field of view of 2 x 2 arcseconds. The mid-resolution mode uses a novel image slicer to dissect and rearrange the micro-pupils produced by a subset of the lenslet array and is a unique capability. Both modes use coronagraphic and apodizing masks to attain contrast ratios of 104−5. SCALES will make ground-breaking measurements of exoplanetary systems. The instrument has a complementary diffraction-limited imaging arm with a field of view of 12 x 12 arcseconds that operates from 1 – 5 microns. The performance over the entire field of view is exquisite both in terms of wavefront error control and spot size, and the design will continue to meet high performance goals after future upgrades to the AO system (which may include an adaptive secondary mirror, a higher actuator count DM, and multi-conjugate wavefront sensors). We give an overview of the work completed and design status.
T36] Daniel Echeverri – Vortex Fiber Nulling Demonstration with the Keck Planet Imager and Characterizer
Vortex fiber nulling (VFN) is an interferometric method for suppressing starlight in order to observe exoplanets at small angular separations from their star, 1/D. This technique may enable the discovery and characterization of young giant planets at separations smaller than conventional coronagraphs can achieve. VFN has been experimentally demonstrated in a laboratory setting with starlight rejection ratios of <5×10-5 in 15% bandwidth broadband light. VFN has now also been deployed to the Keck II Telescope as part of Phase II of the Keck Planet Imager and Characterizer (KPIC) instrument for an on-sky demonstration. Here we present system-level performance measurements of the KPIC VFN mode off-sky as deployed at the telescope. We also present early on-sky results obtained during commissioning nights in the first half of 2022.
T37] Mona El Morsy – Development of a prototype instrument for the direct characterization of young giant exoplanets
On large ground-based telescopes, the combination of extreme adaptive optics (ExAO) and coronagraphy with high-dispersion spectroscopy (HDS), sometimes referred to as high-dispersion coronagraphy (HDC), is emerging as a powerful technique for the direct characterisation of giant exoplanets. The high spectral resolution brings a significant gain in terms of accessible spectral features and enables better separating the stellar and planetary signals. On-going projects such as KPIC/Keck, REACH/Subaru and HiRISE/VLT base their observing strategy on using science fibres, one of which is dedicated to sample the planets signal while the others sample the stellar residuals starlight in the speckle field. The main challenge is to centre the planet’s PSF on the science fibre with an accuracy of less than 0.1 lambda/D. Possible centring strategies are foreseen in the context of the HiRISE project, based on retro-injecting calibration fibres to localise the science fibre’s position or based on a dedicated centring fibre. We implement three approaches and compare their centring accuracy performances using the MITHiC testbed, upgraded to emulate a setup close to the one adopted in HiRISE. The results demonstrate that reaching a specification accuracy of 0.1 lambda/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We have studied the contributors to the centring error in MITHiC and propose a quantification for some of the most impacting terms.
T38] Jules Dallant – A new PACO based method to push the exoplanets detection limits and to estimate their orbital parameters simultaneously
Exoplanets detection by direct imaging remains one of the most challenging field of astronomy. The very high contrast between the host star and its orbiting companions can prevent the exoplanets detection in a single dataset. However, combining the information of several observations of the same targeted star can boost the detection limits to unprecedented levels. We propose a new algorithm named PACOME that optimally combines multi-epoch datasets to improve the detection sensitivity of presumed exoplanets by accounting for their orbital motions. Our method is based on the PACO algorithm that learns the stellar contamination from the data spatial correlations to estimate signalto-noise ratio (SNR) of the brightness of potential orbiting companions. From these unique PACO outputs, PACOME generates a large number of Keplerian orbits and evaluates their likelihood with an optimal multi-epochs detection criterion. The presence of a potential exoplanet can be assessed by the orbital parameters maximising the combined signal. PACOME benefits from PACO’s high sensitivity and is faster than standard multi-epoch algorithms. We demonstrate its efficiency using SPHERE-IRDIS observations recorded in Angular and Spectral Differential Imaging (ADI & ASDI) from the two exoplanetary systems HR 8799 and HD 95086. We demonstrate unprecedented boost in the combined SNR of the known exoplanets and an accurate estimation of their orbital parameters compatible with the literature. New companions to HR 8799 and HD 95086 were not detected in these datasets. In the future, we will adapt PACOME to process SPHERE-IFS data in order to improve the detection limits further and possibly detect new fainter exoplanets.
T39] Quinn Konopacky – The Development of HISPEC for Keck and MODHIS for TMT
HISPEC is a new, high-resolution near-infrared spectrograph being designed for the W.M. Keck II telescope. By offering single-shot, R 100,000 spectroscopy between 1 – 2.5 um, HISPEC will enable spectroscopy of transiting and non-transiting exoplanets in close orbits, direct high-contrast detection and spectroscopy of spatially separated substellar companions, and exoplanet dynamical mass and orbit measurements using precision radial velocity monitoring calibrated with an ultra-stable laser frequency comb. HISPEC is designed to be used with the Keck facility adaptive optics system, coupling light efficiently into single-mode fibers, thereby suppressing fiber modal noise affecting multi-mode fiber-fed spectrographs and reducing sky background and OH emission lines by two orders of magnitude (vs. seeing-limited architectures). Moreover, by using single-mode fiber inputs, we derive a compact, ultra-stable and cost-effective spectrograph design. I will review the current design of HISPEC, which is currently in the final stages of preliminary design and is slated to be on-sky at Keck in 2025. I will describe the innovative technical components of HISPEC that will allow for detailed characterization of directly imaged exoplanets, including plans to enable detection near the diffraction limit. HISPEC is a pathfinder for MODHIS, one of the first light instruments being designed for the Thirty Meter Telescope, and the two instruments are being developed in parallel. I will describe the conceptual design of MODHIS and how it enable transformative science in the era of the extremely large telescopes.
T40] Olivier Absil – Final design and expected performance of the METIS high-contrast imaging modes
The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the three first-generation science instruments for the ELT, funded for construction by ESO and a consortium of research institutes across and beyond Europe. METIS is designed to cover the 3 to 13 m wavelength range, and is due to pass its final design review (FDR) in autumn 2022. Here, we describe how high contrast imaging modes have been added to METIS during its conceptual and detailed design phases. We discuss the main top-level requirements in terms of coronagraphic performance, and how they have been translated into design choices through various trade-offs. We then detail the implementation of the two main coronagraphic solutions selected for METIS, namely the vortex coronagraph and the apodizing phase plate, including their combination with the high-resolution integral field spectrograph of METIS. Using end-to-end simulations, we predict the performance that will be reached on sky by the METIS high contrast imaging modes in presence of residual aberrations from adaptive optics correction, and of various other instrumental errors such as non-common path aberrations, pointing jitter, ELT-M1 cophasing errors, or residual atmospheric dispersion. We also give a detailed description of how water vapor turbulence will affect the METIS high contrast imaging performance, using water vapor measurements from the Very Large Telescope Interferometer, and describe how focal-plane wavefront sensing can mitigate this effect. We finally illustrate with mock observations and data processing that METIS should be capable of directly imaging temperate rocky planets around the nearest stars.
T41] Elisabeth Matthews – Dynamical Masses and Spectroscopic Analysis of Brown Dwarfs: long-period companions with RVs and high contrast imaging.
Relatively little is known about brown dwarf formation mechanisms and evolution, and only a small number of brown dwarfs have dynamical mass measurements. This means that evolutionary tracks are largely uncalibrated. We use long-baseline (>20yr) radial velocity observations collected with the CORALIE spectrograph to identify radial velocity trends that correspond to wide separation, directly detectable low-mass companions. Together, long baseline CORALIE observations and high-contrast imaging with VLT/SPHERE allow us to detect brown dwarf companions, and to measure precise dynamical masses by combining radial velocities with relative and absolute astrometric measurements thereby resolving the m*sin(i) degeneracy typically present in RV studies. Further, SPHERE spectroscopy allows us to determine the temperature, surface gravity, and atmospheric makeup of the companion. I will present our ongoing work to image stars with long-term trends using SPHERE to detect and characterize low-mass companions that are vital to understanding the brown dwarf population. I will particularly focus on HD4113C, a fascinating brown dwarf that shows a clear discrepancy between the dynamically- and isochronally- determined masses. I will present an updated dynamical mass and isochronal mass for the system, and demonstrate that even with an updated analysis of the system this discrepancy persists. I will also discuss our attempts to understand and resolve this discrepancy. For a select few targets, such as Eps Indi Ab, it will soon be possible to extend this work into the planetary mass regime with JWST high contrast imaging.
T42] Kyle Franson – Searching for Planets and Brown Dwarfs around Young Accelerating Stars
Directly imaged planets and brown dwarfs are critical tools for studying the formation, evolution, and atmospheric physics of wide-separation substellar objects. However, imaging campaigns have been limited by the low occurrence rate of long-period planets and brown dwarfs. As a result, only about a dozen exoplanets with separations between 10 and 100 AU have been imaged. Our goal is to overcome these low occurrence rates by targeting stars exhibiting small proper motion differences between Hipparcos and Gaia EDR3 that confer the presence of unseen substellar companions. Over the past two years, we have launched a multi-facility, systematic high-contrast imaging survey of the accelerating stars most likely to harbor long-period giant planets and brown dwarfs. In this talk, I will present an overview of our program, our novel approach to efficient target selection, and early results including the first discovery from this survey.
T43] Rachel Bowens-Rubin – The tale of the Wolf 359b campaign: combining highcontrast imaging and RV data to study a cold Neptunian exoplanet
Wolf 359b is an ice giant exoplanet discovered using HIRES and HARPS radial velocity measurements, orbiting a young (100-350 Myrs) M-dwarf located just 2.39 pc from the Sun. The Wolf 359 systems youth and proximity presents a unique opportunity to directly image an ice giant exoplanet with our current technology. In this talk, I will describe our progress in observing the Wolf 359 system with the W.M. Keck Observatory NIRC2 imager and our collaboration with the radial velocity community. Our multi-technique observing campaign allows us to place the tightest constraints on the mass, orbital position, and thermal energy signature of Wolf 359b to date and delivers insights to the barriers when performing background-limited ground-based imaging observations to detect cold exoplanets at Keck. I will conclude by discussing our future prospects for imaging Wolf 359b at Keck and with JWST.
T44] Emily Rickman – Precise Dynamical Masses of New Directly Imaged Companions from Combining Relative Astrometry, Radial Velocities, and High contrast imaging
Very little is known about giant planets and brown dwarfs at an orbital separation great than 5 AU. And yet, these are important puzzle pieces needed for constraining the uncertainties that exist in giant planet formation and evolutionary models that are plagued by a lack of observational constraints. In order to observationally probe this mass-separation parameter space, direct imaging is necessary but faces the difficulty of low detection efficiency. To utilize the power of direct imaging, pre-selecting companion candidates with long-period radial velocities, coupled with proper anomalies from Hipparcos and Gaia, provide a powerful tool to hunt for the most promising candidates. Not only does this increase the detection efficiency, but this wealth of information removes the degeneracy of unknown orbital parameters, leading to derived dynamical masses which can serve as benchmark objects. With upcoming missions like JWST and Roman, as well as ground-based facilities like the ELT, observing time is valuable and the strategy of direct imaging needs to be re-defined to pre-select targets. Looking further ahead, perfecting these strategies will be necessary as we look towards a large IR/O/UV mission, as recommended by the Astro 2020 decadal survey report, to pinpoint the location of terrestrial planets amenable to direct imaging. I present the detection of new directly imaged companions from VLT/SPHERE with derived precise dynamical masses from combining relative astrometry, radial velocities, and astrometry from Hippacros-Gaia eDR3 accelerations, giving precisely characterized benchmark objects that can be used to test evolutionary models.
T45] Kevin Wagner – Imaging Habitable-Zone Exoplanets with Mid-Infrared Coronagraphy
Mid-infrared coronagraphic imaging is close to enabling the direct detection of nearby habitable-zone exoplanets. The ESO/Breakthrough-sponsored New Earths in the Alpha Centauri Region (NEAR) program on the VLT recently completed the first ultra-deep ( 100 hr) mid-IR exoplanet imaging campaign and demonstrated the first sensitivity to habitable-zone sub-Neptune-sized planets, leaving just a factor of four in sensitivity to be overcome in order to image potentially rocky planets. This talk will describe our ongoing efforts to upgrade the mid-IR capabilities of the LBT based on the lessons from NEAR, including the design of a new high-performance mid-IR coronagraph, which will enable partially bridging this sensitivity gap. Next, we will discuss the prospects for coordinated deep explorations for low-mass habitable-zone planets around targets visible from both the Northern and Southern hemispheres (e.g., Sirius, Epslion Eridani, etc.). Finally, we will conclude with an introduction of our key observational program, LESSONS: The LBT Exploratory Survey for Super-Earths/Sub-Neptunes Orbiting Nearby Stars, and a roadmap toward imaging habitable-zone Earth-sized planets with the ELTs.
T46] Jared Males – The potential, and limits, of high contrast imaging with the ELTs
The 25-39 m ELTs will present us with the chance to image and spectroscopically characterize temperate exoplanets in large numbers. Current 6.5-10 m telescopes may be able to do so for a small number of nearby targets, including Proxima b. Achieving this goal will require extreme adaptive optics (ExAO) coronagraphs performing near the fundamental limits imposed by atmospheric turbulence, dynamic instrumental aberrations, and photon noise. If this performance level can be reached, our detailed modeling of the known nearby planets shows that hundreds of exoplanets will be characterized in reflected starlight from telescopes in both hemispheres. To begin testing these limits we have undertaken an upgrade program for MagAO-X, which will include a full computing system upgrade, new PIAA optics and complex coronagraph mask designs, and the addition of a 1000 actuator incoronagraph DM for high contrast dark hole control. To prepare for the ELT era, we have completed the conceptual design of GMagAO-X, the follow-on instrument for the GMT. To support these efforts we have developed a new end-to-end ExAO performance modeling framework which includes the effects of post-processing. Here we will present an overview of the planned upgrades to MagAO-X; provide highlights of the CoDR for GMagAO-X; describe the target samples for MagAO-X and GMagAO-X as well as similar ELT and TMT instruments; and finally discuss the atmospheric characterization we will perform on these targets.
T47] Nemanja Jovanovic – Phase II of the Keck Planet Imager and Characterizer: Systemlevel Laboratory Characterization
The Keck Planet Imager and Characterizer (KPIC) is a series of upgrades for the Keck II Adaptive Optics system and the NIRSPEC spectrograph to enable diffraction-limited, high-resolution (R>30,000) spectroscopy in the K and L bands. Phase I consisted of single-mode fiber injection/extraction units (FIU/FEU) used in conjunction with a H-band pyramid wavefront sensor. The use of single-mode fibers provides a substantial reduction in sky background as well as an extremely stable line-spread function. Phase II added a 1000-actuator deformable mirror, beam-shaping optics for optimal injection, a vortex coronagraph, provisions for operating at shorter wavebands (y-H), access to laser frequency combs and other upgrades to the FIU/FEU. Phase II was deployed to, and integrated with the Keck II telescope in February 2022. In this paper we present the results of extensive system-level laboratory testing and characterization showing the instruments Phase II throughput, stability, repeatability, and other key performance metrics prior to delivery and during installation at Keck. We also demonstrate the capabilities of the various observing modes enabled by the new system modules using internal test light sources. Finally, we show preliminary results of on-sky tests performed in the first few months of Phase II commissioning along with the next steps for the instrument. Once commissioning of Phase II is complete, KPIC will continue to characterize exoplanets at an unprecedented spectral resolution, thereby growing its already successful track record of 23 detected exoplanets and brown dwarfs from Phase I.
T48] Raphael Galicher (Anthony Boccaletti) – Upgrading the high contrast imaging facility SPHERE: science drivers and instrument choices
SPHERE+ is a proposed upgrade of the SPHERE instrument at VLT, which will boost the current performances of detection and characterization of exoplanets and disks, and will serve as a demonstrator for the future planet finder of the European ELT (PCS). The main science drivers for SPHERE+ are 1/ to access the bulk of the young giant planet population down to the snow line (3-10 au); 2/ to observe fainter and redder targets in the youngest (1 10 Myr) associations compared to those observed with SPHERE to directly study the formation of giant planets in their birth environment; 3/ to improve the level of characterization of exoplanetary atmospheres by increasing the spectral resolution. To achieve these objectives, we are considering to implement two new independent sub-systems. SAXO+, the second stage AO system, is optimized in the infrared with a pyramid wavefront sensor (0.95-1.2um/0.95-1.4um), a dedicated Real-Time Computer, and a High Order DM (24 to 32 linear actuators). SAXO+ should provide a faster correction (from 1 to 3 kHz) and a higher sensitivity to redder targets (+2-3 mag) as compared to SPHERE. MEDRES is a medium resolution integral field spectrograph with a resolution of 1000 (goal 5000) in the J and H bands. MEDRES is based on a very low-noise IR detector to enable very high contrasts. We will give an overview of the science drivers, requirements and key instrumental tradeoff that were done for SPHERE+ to reach the baseline concept. We will also provide preliminary estimates of performances obtained by simulations.
T49] Saavidra Perera – Upgrading the Gemini Planet Imager to GPI 2.0
The Gemini Planet Imager (GPI) is a high contrast imaging instrument designed to directly detect and characterize young, Jupiter-mass exoplanets. After six years of operation at Gemini South in Chile, the instrument is being upgraded and relocated to Gemini North in Hawaii as GPI 2.0. GPI helped establish that Jovian-mass planets have a higher occurrence rate at smaller separations, motivating several sub-system upgrades to obtain deeper contrasts (up to 20 times improvement to the current limit), particularly at small inner working angles. Changes will be made to (i) the adaptive optics system, by replacing the current Shack-Hartmann wavefront sensor (WFS) with a pyramid WFS and a custom EMCCD, (ii) the integral field spectrograph, by employing a new set of prisms to enable an additional broadband (Y-K band) low spectral resolution mode, as well as replacing the pupil viewer camera with a faster, lower noise C-RED2 camera (iii) the calibration interferometer, by upgrading the low-order WFS used for internal alignment and on-sky target tracking with a C-RED2 camera and replacing the calibration high-order WFS used for measuring and correcting non-common path aberrations with a self coherent camera, (iv) the apodized-pupil Lyot coronagraph designs and (v) the software, to enable high-efficiency queue operations at Gemini North. GPI 2.0 is expected to go on-sky in late 2023 or early 2024. Here I will present the key upgrades as well as the latest timeline for operations and current status.
T50] Michael Fitzgerald – The Planetary Systems Imager for TMT: Overview and Status
We will provide a summary review of the scientific and technical capabilities and the overall project status of the Planetary Systems Instrument (PSI), a second-generation instrumentation suite for the TMT. The instrument seeks to determine the composition and energy balance of exoplanets through the joint measurement of planet-reflected starlight and thermal emission, as well as constrain planet formation and evolution scenarios through high-spectral-resolution characterization of exoplanet atmospheres. The PSI instrument concept operates from optical to thermal infrared wavelengths, combining high-order AO correction with pupil- and focal-plane wavefront sensing, coronagraphs, imaging and low-resolution integral-field spectroscopy, as well as fiber-coupled high-resolution spectrometers. The modular design enables simultaneous characterization of exoplanets at multiple wavelengths, allows for phased deployment and commissioning, and provides upgrade paths to accommodate potential technological advances. We will provide an overview of the past two years of development, including description of the key scientific and technical requirement development and flowdown, AO and science output performance simulation and the development of the PSISIM simulation framework, optical conceptual design of the front-end AO system, and the status of precursor instrumentation and techniques.
T51] Dan Sirbu – Exoplanet Yield Sensitivity for the Hybrid Lyot Coronagraph from end-to-end modeling for LUVOIR-A
NASA’s future direct imaging flagship mission will require telescope mirror segmentation to survey a statistically significant population of nearby stellar systems by increasing aperture size beyond the limits set by traditional monolithic apertures; however, segmentation also represents an additional challenge due to the introduction of temporal pupil discontinuities in terms of both phase and amplitude. Modeling of the integrated performance of the coronagraph with the expected dynamical profile of the telescope can provide realistic estimates of the mission’s science yields. We present results of a study using the Hybrid Lyot coronagraph with the Large UV / Optical /Infrared (LUVOIR) mission’s 15-m on-axis, segmented optical telescope assembly (OTA). We have developed a high-fidelity, end-toend model as part of the Segmented Coronagraph Design and Analysis (SCDA) group that includes diffractive optical propagations at the 1 × 10−10 contrast level across the optical train including the OTA and intermediate re-imaging optics inside the coronagraph instrument. We perform a sensitivity analysis to assess the contrast sensitivity to wavefront perturbations for a set of key telescope terms including segment-level low-order and mid-spatial frequency aberrations and evaluate expected exoplanet yields obtained in the presence of these sets of aberrations. Industry-provided segment-level wavefront aberration datasets are input to the end-to-end model: (1) thermal gradients and accelerations, and (2) telescope dynamics including line-of-sight and segment jitter. Dynamically averaged PSFs in the presence of aberrations are fed into Altruistic Yield Optimization (AYO), a mission design reference simulator, that then assesses the scientific yield sensitivities.
T52] Garima Singh – End-to-end high-contrast imaging simulations with the LLOWFS and FAST sensors for TMT.
Thirty-Meter Telescope (TMT) has the potential to revolutionize the field of direct imaging of exoplanets by enabling the imaging and low-resolution spectroscopy of Neptune or Super-Earth exoplanets in the habitable zone of nearby stars. Imaging mature gas planets at small angles around nearby stars require raw contrast limits of 10-7-10-9 in near-infrared. Such contrast goals are currently unachievable with state-of-the-art high contrast imaging (HCI) instruments, mainly because the region of high-contrast at small angles is still dominated by the speckle noise. To address this issue on the NEW-EARTH testbed, we have been working on implementing the Lyot-stop low-order wavefront sensor (LLOWFS) to freeze the speckles and the Fast Atmospheric Self-Coherent Camera Technique (FAST) to suppress the quasi-static speckles close to the inner working angle of a coronagraph. This fusion of LLOWFS and FAST is being developed for the upcoming CAL2.0 unit of Gemini Planet Imager (GPI) and SPIDERS prototype for Subaru Telescope. Based on the encouraging results obtained in the laboratory thus far (1sigma raw contrast level of 10-7 in the region 5-12 lambda/D), we started developing an end-to-end simulation of an HCI instrument employing both the LLOWFS and the FAST for TMT. Our simulation feeds on the post-NFIRAOS residual phase maps of the adaptive optics system of TMT and makes use of the TMT-pupil optimized apodizer, FAST optimized focal plane mask, LLOWFS and FAST sensors. In this presentation, we will present the preliminary contrast results under the realistic static and quasi-static GPI-residuals.
T53] Jean-Baptiste Ruffio – High resolution spectroscopy of directly imaged exoplanets with KPIC
The Keck Planet Imager and Characterizer (KPIC) has recently demonstrated the first detections of several high-contrast planets and sub-stellar companions at high spectral resolution (R 35,000). KPIC consists of a series of upgrades to the Keck II adaptive optics (AO) system, the NIRC2 imager, and the NIRSPEC spectrograph. By resolving molecular lines, high resolution spectroscopy provides a more detailed look into planetary atmospheres by allowing measurements such as their radial velocity, spin, atmospheric composition, or even doppler imaging. On behalf of the KPIC team, I will highlight some of the early KPIC science results which for example include the first spin measurement of the HR 8799 planets, and atmospheric composition of several benchmark brown-dwarf companions validating atmospheric retrievals at high spectral resolution. With over 20 detections and counting, we are carrying a survey of exoplanets and brown-dwarf companions with the goal of identifying trends in exoplanet composition and spin that will inform different planet formation pathways. The instrument will undergo several upgrades in the future, which will result in improved sensitivity and extended wavelength coverage.
T54] Evert Nasedkin – Four of a Kind: A Systematic Characterization of the HR8799 planets.
High contrast imaging (HCI) provides a novel window into the atmospheres of young exoplanets, though the robust interpretation of results comes with many challenges. In this talk I will explore the systematic characterization of the HR8799 system using new VLTI/GRAVITY data combined with new and archival data from SPHERE, GPI, CHARIS, ALES and OSIRIS in order to provide the best picture of the planetary atmospheres across a broad wavelength range. Much of the existing data was reprocessed, and we compare the impact of data processing choices on the extracted planetary properties through injection testing into SPHERE and GPI HCI datasets. Using petitRADTRANS in a Bayesian retrieval framework, we compare a suite of state-of-the-art models applied to each of the targets in order to measure atmospheric properties. We present the first C/O ratios of each of these planets as derived through disequilibrium and free chemistry retrievals, and discuss potential formation mechanisms that could have led to the current planetary configuration.
T55] Simon Petrus – X-SHYNE: a new sample of young, cold, low-mass planetary analogs
The X-SHYNE project aims at characterizing a sample of 40 young (8-150 Myr), free-floating exoplanetary (10-25 MJup) analogs, covering spectral types between L and mid-T, using the VLT/XShooter instrument (from 0.6 to 2.5 microns) at medium spectral resolution (R 8000) . The prime objective is to explore the physical mechanisms occurring in the atmospheres of young giant planets, and to search for formation tracers through the estimation of fundamental parameters (temperature, surface gravity, metallicity, C/O, etc.). ForMoSA is a Bayesian tool (based on the nested sampling algorithm) that can be used to estimate these parameters by comparing the X-Shooter high signal-to-noise spectra with the predictions of atmospheric models (BT-SETTL, Exo-REM, ATMO). In this talk, I will (i) introduce the spectral diversity offered by the X-SHYNE spectra, (ii) show the preliminary atmospheric characterization of the sample performed with ForMoSA, (iii) illustrate their relevance for the interpretation of todays imaged exoplanets, (iv) finally present the potential of the forward modeling approach with the current generation of atmospheric models for future applications with JWST.
T56] Beth Biller – Variability of Young, Giant Exoplanets : Opportunity or Obstacle?
Free-floating young planetary mass objects are among the most variable substellar objects known to date, with variability amplitudes of >20% in some cases (Bowler et al. 2020). This variability is likely due to asymmetric top-of-the-atmosphere structure, potentially driven by patchy thin and thick clouds (Apai et al. 2013, 2017). Understanding this structure provides critical constraints for atmospheric models of brown dwarfs and giant exoplanets. However, high-amplitude variability may prove an observational challenge for accurate spectroscopy of young, late-L exoplanet companions such as the HR 8799 planets, which are likely comparably variable to their free-floating counterparts. Here, I will discuss results and lessons learned from a VLT-SPHERE search for variability in the HR 8799 planets (Biller et al. 2021) as well as a large-scale, coordinated ongoing variability monitoring campaign for the young, late-L companion VHS 1256b, a target for JWST Early Release Science program 1386 (PI Hinkley). At some epochs, VHS 1256b varies by >20% over 8 hours in the near IR (Bowler et al. 2020, Zhou et al. 2020, 2022) and may be up to 10% variable during the 4-hour long JWST ERS observations. Constraining its variability ahead of these observations is critical for maximizing the science return of the JWST observations.