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1. Possible Carbon Dioxide above the Thick Aerosols of GJ 1214 b

Author

Everett Schlawin, Kazumasa Ohno, Taylor J. Bell, Matthew M. Murphy, Luis Welbanks, Thomas G. Beatty, Thomas P. Greene, Jonathan J. Fortney, Vivien Parmentier, Isaac R. Edelman, Samuel Gill, David R. Anderson, Peter J. Wheatley, Gregory W. Henry, Nishil Mehta, Laura Kreidberg, and Marcia J. Rieke

Subjects
Exoplanet atmospheric composition, Exoplanet atmospheres, Mini Neptunes, James Webb Space Telescope, Transmission spectroscopy, Astrophysics, QB460-466
Abstract

Sub-Neptune planets with radii smaller than Neptune (3.9 R _⊕ ) are the most common type of planet known to exist in the Milky Way, even though they are absent in the solar system. These planets can potentially have a large diversity of compositions as a result of different mixtures of rocky material, icy material, and gas accreted from a protoplanetary disk. However, the bulk density of a sub-Neptune, informed by its mass and radius alone, cannot uniquely constrain its composition; atmospheric spectroscopy is necessary. GJ 1214 b, which hosts an atmosphere that is potentially the most favorable for spectroscopic detection of any sub-Neptune, is instead enshrouded in aerosols (thus showing no spectroscopic features), hiding its composition from view at previously observed wavelengths in its terminator. Here, we present a JWST NIRSpec transmission spectrum from 2.8 to 5.1 μ m that shows signatures of CO _2 and CH _4 , expected at high metallicity. A model containing both these molecules is preferred by 3.3 σ and 3.6 σ as compared to a featureless spectrum for two different data analysis pipelines, respectively. Given the low signal-to-noise of the features compared to the continuum, however, more observations are needed to confirm the CO _2 and CH _4 signatures and better constrain other diagnostic features in the near-infrared. Further modeling of the planet’s atmosphere, interior structure and origins will provide valuable insights about how sub-Neptunes like GJ 1214 b form and evolve.

Published
2024
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2. Sulfur Dioxide and Other Molecular Species in the Atmosphere of the Sub-Neptune GJ 3470 b

Author

Thomas G. Beatty, Luis Welbanks, Everett Schlawin, Taylor J. Bell, Michael R. Line, Matthew Murphy, Isaac Edelman, Thomas P. Greene, Jonathan J. Fortney, Gregory W. Henry, Sagnick Mukherjee, Kazumasa Ohno, Vivien Parmentier, Emily Rauscher, Lindsey S. Wiser, and Kenneth E. Arnold

Subjects
Exoplanet atmospheres, Exoplanet atmospheric composition, Exoplanet formation, Astrophysics, QB460-466
Abstract

We report observations of the atmospheric transmission spectrum of the sub-Neptune exoplanet GJ 3470 b taken using the Near-Infrared Camera on JWST. Combined with two archival Hubble Space Telescope/Wide-Field Camera 3 transit observations and 15 archival Spitzer transit observations, we detect water, methane, sulfur dioxide, and carbon dioxide in the atmosphere of GJ 3470 b, each with a significance of >3 σ . GJ 3470 b is the lowest-mass—and coldest—exoplanet known to show a substantial sulfur dioxide feature in its spectrum, at M _p = 11.2 M _⊕ and T _eq = 600 K. This indicates that disequilibrium photochemistry drives sulfur dioxide production in exoplanet atmospheres over a wider range of masses and temperatures than has been reported or expected. The water, carbon dioxide, and sulfur dioxide abundances we measure indicate an atmospheric metallicity of approximately 100× solar. We see further evidence for disequilibrium chemistry in our inferred methane abundance, which is significantly lower than expected from equilibrium models consistent with our measured water and carbon dioxide abundances.

Published
2024
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3. Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum

Author

Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, and Marcia Rieke

Subjects
Exoplanet astronomy, Exoplanet atmospheres, Exoplanet atmospheric composition, Infrared spectroscopy, Chemical enrichment, James Webb Space Telescope, Astronomy, QB1-991
Abstract

WASP-69 b is a hot, inflated, Saturn-mass planet (0.26 M _Jup ) with a zero-albedo equilibrium temperature of 963 K. Here, we report the JWST 2–12 μ m emission spectrum of the planet consisting of two eclipses observed with NIRCam grism time series and one eclipse observed with the MIRI low-resolution spectrometer (LRS). The emission spectrum shows absorption features of water vapor, carbon dioxide, and carbon monoxide, but no strong evidence for methane. WASP-69 b’s emission spectrum is poorly fit by cloud-free homogeneous models. We find three possible model scenarios for the planet: (1) a scattering model that raises the brightness at short wavelengths with a free geometric albedo parameter; (2) a cloud-layer model that includes high-altitude silicate aerosols to moderate long-wavelength emission; and (3) a two-region model that includes significant dayside inhomogeneity and cloud opacity with two different temperature–pressure profiles. In all cases, aerosols are needed to fit the spectrum of the planet. The scattering model requires an unexpectedly high geometric albedo of 0.64. Our atmospheric retrievals indicate inefficient redistribution of heat and an inhomogeneous dayside distribution, which is tentatively supported by MIRI LRS broadband eclipse maps that show a central concentration of brightness. Our more plausible models (2 and 3) retrieve chemical abundances enriched in heavy elements relative to solar composition by 6× to 14× solar and a C/O ratio of 0.65–0.94, whereas the less plausible highly reflective scenario (1) retrieves a slightly lower metallicity and lower C/O ratio.

Published
2024
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4. Absolute Calibration. IV. Use of G-type Stars as Primary Calibrators

Author

G. H. Rieke, Everett Schlawin, Charles R. Proffitt, and Christopher Willmer

Subjects
Fundamental parameters of stars, Infrared photometry, Astronomical techniques, Astronomy, QB1-991
Abstract

We demonstrate an approach to determine spectral energy distribution (SED) templates that are accurate to the 1% level from the visible through the infrared for nearby (unextincted) solar-type stars. Our approach is based only on measurements of T _eff , log( g ), and M/H and the use of standard theoretical SED models. The success of this approach confirms that the existing absolute calibration is likely to be accurate to this level throughout this spectral range. We then demonstrate how to measure and correct for extinction, allowing extension of this calibration approach to faint levels (and more distant stars). We provide template SEDs in digital form for 11 G-dwarf stellar calibrators.

Published
2024
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5. First Sample of Hα+[O iii]λ5007 Line Emitters at z > 6 Through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line-luminosity Functions

Author

Fengwu Sun, Eiichi Egami, Nor Pirzkal, Marcia Rieke, Stefi Baum, Martha Boyer, Kristan Boyett, Andrew J. Bunker, Alex J. Cameron, Mirko Curti, Daniel J. Eisenstein, Mario Gennaro, Thomas P. Greene, Daniel Jaffe, Doug Kelly, Anton M. Koekemoer, Nimisha Kumari, Roberto Maiolino, Michael Maseda, Michele Perna, Armin Rest, Brant E. Robertson, Everett Schlawin, Renske Smit, John Stansberry, Ben Sunnquist, Sandro Tacchella, Christina C. Williams, and Christopher N. A. Willmer

Subjects
Emission line galaxies, High-redshift galaxies, James Webb Space Telescope, Starburst galaxies, Galaxy spectroscopy, Astrophysics, QB460-466
Abstract

We present a sample of four emission-line galaxies at z = 6.11–6.35 that were serendipitously discovered using the commissioning data for the James Webb Space Telescope (JWST)/NIRCam wide-field slitless spectroscopy mode. One of them (at z = 6.11) has been reported previously, while the others are new discoveries. These sources are selected by the secure detections of both [O iii ] λ 5007 and H α lines with other fainter lines, which were tentatively detected in some cases (e.g., [O ii ] λ 3727, [O iii ] λ 4959). In the [O iii ]/H β –[N ii ]/H α Baldwin–Phillips–Terlevich diagram, these galaxies occupy the same parameter space as that of z ∼ 2 star-forming galaxies, indicating that they have been enriched rapidly to subsolar metallicities (∼0.4 Z _⊙ ), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong H α lines suggests a higher ionizing photon production efficiency within galaxies in the early universe. We find brightening of the [O iii ] λ 5007 line-luminosity function (LF) from z = 3 to 6, and weak or no redshift evolution of the H α line LF from z = 2 to 6. Both LFs are underpredicted at z ∼ 6 by a factor of ∼10 in certain cosmological simulations. This further indicates a global Ly α photon escape fraction of 7%–10% at z ∼ 6, which is slightly lower than previous estimates through the comparison of the UV-derived star formation rate density and Ly α luminosity density. Our sample recovers ${66}_{-44}^{+128}$ % of z = 6.0–6.6 galaxies in the survey volume with stellar masses greater than 5 × 10 ^8 M _⊙ , suggesting the ubiquity of strong H α and [O iii ] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST.

Published
2023
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6. Planet Eclipse Mapping with Long-term Baseline Drifts

Author

Everett Schlawin, Ryan Challener, Megan Mansfield, Emily Rauscher, Arthur Adams, and Jacob Lustig-Yaeger

Subjects
Eclipses, Hot Jupiters, Exoplanet atmospheres, Planetary atmospheres, Gaussian Processes regression, Astronomical techniques, Astronomy, QB1-991
Abstract

High-precision lightcurves combined with eclipse-mapping techniques can reveal the horizontal and vertical structure of a planet’s thermal emission and the dynamics of hot Jupiters. Someday, they even may reveal the surface maps of rocky planets. However, inverting lightcurves into maps requires an understanding of the planet, star, and instrumental trends because they can resemble the gradual flux variations as the planet rotates (i.e., partial phase curves). In this work, we simulate lightcurves with baseline trends and assess the impact on planet maps. Baseline trends can be erroneously modeled by incorrect astrophysical planet map features, but there are clues to avoid this pitfall in both the residuals of the lightcurve during eclipse and sharp features at the terminator of the planet. Models that use a Gaussian process or polynomial to account for a baseline trend successfully recover the input map even in the presence of systematics but with worse precision for the m = 1 spherical harmonic terms. This is also confirmed with the ThERESA eigencurve method where fewer lightcurve terms can model the planet without correlations between the components. These conclusions help aid the decision on how to schedule observations to improve map precision. If the m = 1 components are critical, such as measuring the east/west hot-spot shift on a hot Jupiter, better characterization of baseline trends can improve the m = 1 terms’ precision. For latitudinal north/south information from m ≠ 1 mapping terms, it is preferable to obtain high signal to noise at ingress/egress with more eclipses.

Published
2023
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7. The PEPSI Exoplanet Transit Survey (PETS). II. A Deep Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with Emission and Transmission Spectroscopy

Author

Marshall C. Johnson, Ji Wang, Anusha Pai Asnodkar, Aldo S. Bonomo, B. Scott Gaudi, Thomas Henning, Ilya Ilyin, Engin Keles, Luca Malavolta, Matthias Mallonn, Karan Molaverdikhani, Valerio Nascimbeni, Jennifer Patience, Katja Poppenhaeger, Gaetano Scandariato, Everett Schlawin, Evgenya Shkolnik, Daniela Sicilia, Alessandro Sozzetti, Klaus G. Strassmeier, Christian Veillet, and Fei Yan

Subjects
Exoplanet astronomy, Exoplanet atmospheres, Transmission spectroscopy, Astronomy, QB1-991
Abstract

Recent observations have shown that the atmospheres of ultrahot Jupiters (UHJs) commonly possess temperature inversions, where the temperature increases with increasing altitude. Nonetheless, which opacity sources are responsible for the presence of these inversions remains largely observationally unconstrained. We used LBT/PEPSI to observe the atmosphere of the UHJ KELT-20 b in both transmission and emission in order to search for molecular agents which could be responsible for the temperature inversion. We validate our methodology by confirming a previous detection of Fe i in emission at 16.9 σ . Our search for the inversion agents TiO, VO, FeH, and CaH results in non-detections. Using injection-recovery testing we set 4 σ upper limits upon the volume mixing ratios for these constituents as low as ∼1 × 10 ^−9 for TiO. For TiO, VO, and CaH, our limits are much lower than expectations from an equilibrium chemical model, while we cannot set constraining limits on FeH with our data. We thus rule out TiO and CaH as the source of the temperature inversion in KELT-20 b, and VO only if the line lists are sufficiently accurate.

Published
2023
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8. JWST NIRCam Defocused Imaging Photometric Stability Performance and How It Can Sense Mirror Tilts

Author

Everett Schlawin, Thomas Beatty, Brian Brooks, Nikolay K Nikolov, Thomas P Greene, Nestor Espinoza, Kayli Glidic, Keith Baka, Eiichi Egami, John Stansberry, Martha Boyer, Mario Gennaro, Jarron Leisenring, Bryan Hilbert, Karl Misselt, Doug Kelly, Alicia Canipe, Charles A Beichman, Mateo Correnti, J Scott Knight, Alden Jurling, Marshall D Perrin, Lee D Feinberg, Michael McElwain, Nicholas Bond, David Ciardi, Sarah Kendrew, and Marcia Rieke

Subjects
Astronomy
Abstract

We use JWST NIRCam short-wavelength photometry to capture a transit lightcurve of the exoplanet HAT-P-14 b to assess performance as part of instrument commissioning. The short-wavelength precision is 152 ppm per 27 s integration as measured over the full time series compared to a theoretical limit of 107 ppm, after corrections to spatially correlated 1/f noise. Persistence effects from charge trapping are well fit by an exponential function with short characteristic timescales, settling on the order of 5–15 minutes. The short-wavelength defocused photometry is also uniquely well suited to measure the real-time wave-front error of JWST. Analysis of the images and reconstructed wave-front maps indicates that two different hexagonal primary mirror segments exhibited “tilt events,” where they changed orientation rapidly in less than ∼1.4 s. In some cases, the magnitude and timing of the flux jumps caused by tilt events can be accurately predicted with a telescope model. These tilt events can be sensed by simultaneous longer-wavelength NIRCam grism spectral images alone in the form of changes to the point-spread function, diagnosed from the full width at half maximum. They can also be sensed with the fine guidance sensor instrument from difference images. Tilt events possibly from sudden releases of stress in the backplane structure behind the mirrors were expected during the commissioning period because they were found in ground-based testing. Tilt events have shown signs of decreasing in frequency but have not disappeared completely. The detectors exhibit some minor (less than 1%) deviations from linear behavior in the first few groups of each integration, potentially impacting absolute fluxes and transit depths on bright targets, where only a handful of groups are possible. Overall, the noise is within 50% of the theoretical photon noise and read noise. This bodes well for high-precision measurements of transiting exoplanets and other time variable targets.

Published
2023
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10. JWST Noise Floor. II. Systematic Error Sources in JWST NIRCam Time Series

Author

Everett Schlawin, Jarron Leisenring, Michael W McElwain, Karl Misselt, Kenneth Don, Thomas P Greene, Thomas Beatty, Nikolay Nikolov, Douglas Kelly, and Marcia Rieke

Subjects
Astronomy
Abstract

The James Webb Space Telescope (JWST) holds great promise for characterizing atmospheres of transiting exoplanets, potentially providing insights into Earth-sized planets within the habitable zones of M-dwarf host stars if photon-limited performance can be achieved. Here, we discuss the systematic error sources that are expected to be present in grism time-series observations with the NIRCam instrument. We find that pointing jitter and high-gain antenna moves in addition to the detectors' subpixel crosshatch patterns will produce relatively small variations (less than 6 parts per million, ppm). The time-dependent aperture losses due to thermal instabilities in the optics can also be kept to below 2 ppm. To achieve these low noise values, it is important to employ a sufficiently large (more than 1farcs1) extraction aperture. Persistence due to charge-trapping will have a minor (less than 3 ppm) effect on the time series 20 minutes into an exposure and is expected to play a much smaller role than it does for the Hubble Space Telescope WFC3 detectors. We expect detector temperature fluctuations to contribute less than 3 ppm. In total, our estimated noise floor from known systematic error sources is only 9 ppm per visit. We urge caution, however, because unknown systematic error sources could be present in flight and will only be measurable on astrophysical sources such as quiescent stars. We find that reciprocity failure may introduce a perennial instrument offset at the 40 ppm level, so corrections may be needed when a multi-instrument multi-observatory spectrum is stitched together over wide wavelength ranges.

Published
2021
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12. JWST Noise Floor. I. Random Error Sources in JWST NIRCam Time Series

Author

Everett Schlawin, Jarron Leisenring, Karl Misselt, Thomas P Greene, Michael W McElwain, Thomas Beatty, and Marcia Rieke

Subjects
Astronomy
Abstract

James Webb Space Telescope (JWST) transmission and emission spectra will provide invaluable glimpses of transiting exoplanet atmospheres, including possible biosignatures. This promising science from JWST, however, will require exquisite precision and understanding of systematic errors that can impact the time series of planets crossing in front of and behind their host stars. Here, we provide estimates of the random noise sources affecting JWST Near-Infrared Camera (NIRCam) time-series data on the integration-to-integration level. We find that 1/ f noise can limit the precision of grism time series for two groups (230–1000 ppm depending on the extraction method and extraction parameters) but will average down like the square root of N frames/reads. The current NIRCam grism time-series mode is especially affected by 1/ f noise because its GRISMR dispersion direction is parallel to the detector fast-read direction, but could be alleviated in the GRISMC direction. Care should be taken to include as many frames as possible per visit to reduce this 1/ f noise source: thus, we recommend the smallest detector subarray sizes one can tolerate, four output channels, and readout modes that minimize the number of skipped frames (RAPID or BRIGHT2). We also describe a covariance-weighting scheme that can significantly lower the contributions from 1/ f noise as compared to sum extraction. We evaluate the noise introduced by preamplifier offsets, random telegraph noise, and high dark current resistor capacitor (RC) pixels and find that these are correctable below 10 ppm once background subtraction and pixel masking are performed. We explore systematic error sources in a companion paper.

Published
2020
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14. Early Release Science of the exoplanet WASP-39b with JWST NIRISS

Author

Adina D. Feinstein, Michael Radica, Luis Welbanks, Catriona Anne Murray, Kazumasa Ohno, Louis-Philippe Coulombe, Néstor Espinoza, Jacob L. Bean, Johanna K. Teske, Björn Benneke, Michael R. Line, Zafar Rustamkulov, Arianna Saba, Angelos Tsiaras, Joanna K. Barstow, Jonathan J. Fortney, Peter Gao, Heather A. Knutson, Ryan J. MacDonald, Thomas Mikal-Evans, Benjamin V. Rackham, Jake Taylor, Vivien Parmentier, Natalie M. Batalha, Zachory K. Berta-Thompson, Aarynn L. Carter, Quentin Changeat, Leonardo A. dos Santos, Neale P. Gibson, Jayesh M. Goyal, Laura Kreidberg, Mercedes López-Morales, Joshua D. Lothringer, Yamila Miguel, Karan Molaverdikhani, Sarah E. Moran, Giuseppe Morello, Sagnick Mukherjee, David K. Sing, Kevin B. Stevenson, Hannah R. Wakeford, Eva-Maria Ahrer, Munazza K. Alam, Lili Alderson, Natalie H. Allen, Natasha E. Batalha, Taylor J. Bell, Jasmina Blecic, Jonathan Brande, Claudio Caceres, S. L. Casewell, Katy L. Chubb, Ian J. M. Crossfield, Nicolas Crouzet, Patricio E. Cubillos, Leen Decin, Jean-Michel Désert, Joseph Harrington, Kevin Heng, Thomas Henning, Nicolas Iro, Eliza M.-R. Kempton, Sarah Kendrew, James Kirk, Jessica Krick, Pierre-Olivier Lagage, Monika Lendl, Luigi Mancini, Megan Mansfield, E. M. May, N. J. Mayne, Nikolay K. Nikolov, Enric Palle, Dominique J. M. Petit dit de la Roche, Caroline Piaulet, Diana Powell, Seth Redfield, Laura K. Rogers, Michael T. Roman, Pierre-Alexis Roy, Matthew C. Nixon, Everett Schlawin, Xianyu Tan, P. Tremblin, Jake D. Turner, Olivia Venot, William C. Waalkes, Peter J. Wheatley, Xi Zhang, University of St Andrews. School of Physics and Astronomy, Feinstein, Adina D [0000-0002-9464-8101], Line, Michael R [0000-0001-6247-8323], Rustamkulov, Zafar [0000-0003-4408-0463], Apollo - University of Cambridge Repository, Feinstein, Adina D. [0000-0002-9464-8101], and Line, Michael R. [0000-0001-6247-8323]

Subjects
Extraterrestrial Environment, 639/33/445/862, FOS: Physical sciences, 610 Medicine & health, 5109 Space Sciences, 140, QB Astronomy, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), QC, QB, Earth and Planetary Astrophysics (astro-ph.EP), Multidisciplinary, Settore FIS/05, Spectrum Analysis, article, Water, 639/33/34/862, 3rd-DAS, Oxygen, QC Physics, Astrophysics - Solar and Stellar Astrophysics, MCP, Potassium, 570 Life sciences, biology, Astrophysics - Instrumentation and Methods for Astrophysics, 51 Physical Sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

Transmission spectroscopy provides insight into the atmospheric properties and consequently the formation history, physics, and chemistry of transiting exoplanets. However, obtaining precise inferences of atmospheric properties from transmission spectra requires simultaneously measuring the strength and shape of multiple spectral absorption features from a wide range of chemical species. This has been challenging given the precision and wavelength coverage of previous observatories. Here, we present the transmission spectrum of the Saturn-mass exoplanet WASP-39b obtained using the SOSS mode of the NIRISS instrument on the JWST. This spectrum spans $0.6 - 2.8 \mu$m in wavelength and reveals multiple water absorption bands, the potassium resonance doublet, as well as signatures of clouds. The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favoring a heavy element enhancement ("metallicity") of $\sim 10 - 30 \times$ the solar value, a sub-solar carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are best explained by wavelength-dependent, non-gray clouds with inhomogeneous coverage of the planet's terminator., Comment: 48 pages, 12 figures, 2 tables. Under review at Nature

Published
2023

15. Performance of NIRCam on JWST in Flight

Author

Marcia J. Rieke, Douglas M. Kelly, Karl Misselt, John Stansberry, Martha Boyer, Thomas Beatty, Eiichi Egami, Michael Florian, Thomas P. Greene, Kevin Hainline, Jarron Leisenring, Thomas Roellig, Everett Schlawin, Fengwu Sun, Lee Tinnin, Christina C. Williams, Christopher N. A. Willmer, Debra Wilson, Charles R. Clark, Scott Rohrbach, Brian Brooks, Alicia Canipe, Matteo Correnti, Audrey DiFelice, Mario Gennaro, Julian Girard, George Hartig, Bryan Hilbert, Anton M. Koekemoer, Nikolay K. Nikolov, Norbert Pirzkal, Armin Rest, Massimo Robberto, Ben Sunnquist, Randal Telfer, Chi Rai Wu, Malcolm Ferry, Dan Lewis, Stefi Baum, Charles Beichman, René Doyon, Alan Dressler, Daniel J. Eisenstein, Laura Ferrarese, Klaus Hodapp, Scott Horner, Daniel T. Jaffe, Doug Johnstone, John Krist, Peter Martin, Donald W. McCarthy, Michael Meyer, George H. Rieke, John Trauger, and Erick T. Young

Subjects
Space and Planetary Science, Astronomy and Astrophysics
Abstract

The Near Infrared Camera for the James Webb Space Telescope (JWST) is delivering the imagery that astronomers have hoped for ever since JWST was proposed back in the 1990s. In the Commissioning Period that extended from right after launch to early 2022 July, NIRCam has been subjected to a number of performance tests and operational checks. The camera is exceeding prelaunch expectations in virtually all areas, with very few surprises discovered in flight. NIRCam also delivered the imagery needed by the Wavefront Sensing Team for use in aligning the telescope mirror segments.

Published
2023

16. JWST/NIRCam Coronagraphy: Commissioning and First On-Sky Results

Author

Julien H. Girard, Jarron Leisenring, Jens Kammerer, Mario Gennaro, Marcia Rieke, John Stansberry, Armin Rest, Eiichi Egami, Ben Sunnquist, Martha L. Boyer, Alicia Canipe, Matteo Correnti, Bryan Hilbert, Marshall D. Perrin, Laurent Pueyo, Rémi Soummer, Marsha Allen, Howard Bushouse, Jonathan Aguilar, Brian Brooks, Dan Coe, audrey DiFelice, David Golimowski, George Hartig, Dean Hines, Anton Koekemoer, Bryony Nickson, Nikolay Nikolov, Vera Platais, Nor Prizkal, Massimo Robberto, Anand Sivaramakrishnan Sivaramakrishnan, Sangmo Tony Sohn, Randal Telfer, Chi Ray Wu, Thomas Beatty, Michael Florian, Kevin Hainline, Doug Kelly, Karl Misselt, Everett Schlawin, Fengwu Sun, Christina Williams, Christopher Willmer, Christopher Stark, Marie Ygouf, Aarynn L. Carter, Charles Beichman, Thomas P. Greene, Thomas Roellig, John Krist, Jea Adams, Jason Wang, Charles R. Clark, Dan Lewis, and Malcolm Ferry

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics - Instrumentation and Detectors, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Optics (physics.optics), Astrophysics - Earth and Planetary Astrophysics, Physics - Optics
Abstract

In a cold and stable space environment, the James Webb Space Telescope (JWST or "Webb") reaches unprecedented sensitivities at wavelengths beyond 2 microns, serving most fields of astrophysics. It also extends the parameter space of high-contrast imaging in the near and mid-infrared. Launched in late 2021, JWST underwent a six month commissioning period. In this contribution we focus on the NIRCam Coronagraphy mode which was declared "science ready" on July 10 2022, the last of the 17 JWST observing modes. Essentially, this mode will allow to detect fainter/redder/colder (less massive for a given age) self-luminous exoplanets as well as other faint astrophysical signal in the vicinity of any bright object (stars or galaxies). Here we describe some of the steps and hurdles the commissioning team went through to achieve excellent performances. Specifically, we focus on the Coronagraphic Suppression Verification activity. We were able to produce firm detections at 3.35$\mu$m of the white dwarf companion HD 114174 B which is at a separation of $\simeq$ 0.5" and a contrast of $\simeq$ 10 magnitudes ($10^{4}$ fainter than the K$\sim$5.3 mag host star). We compare these first on-sky images with our latest, most informed and realistic end-to-end simulations through the same pipeline. Additionally we provide information on how we succeeded with the target acquisition with all five NIRCam focal plane masks and their four corresponding wedged Lyot stops., Comment: 23 pages, 18 figures, to appear in the Proceedings of the SPIE Astronomical Telescopes + Instrumentation (2022)

Published
2022

17. Atmospheric Characterization of Hot Jupiter CoRoT-1 b Using the Wide Field Camera 3 on the Hubble Space Telescope

Author

Kayli Glidic, Everett Schlawin, Lindsey Wiser, Yifan Zhou, Drake Deming, and Michael Line

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Space and Planetary Science, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Exoplanet CoRoT-1 b is intriguing because we predict it to be a transitional planet between hot Jupiters (equilibrium temperatures ~ 1500 K) and ultra-hot Jupiters (equilibrium temperatures > 2000 K). In 2012, observations of CoRoT-1 b included one primary transit and three secondary eclipses with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) combined with the G141 grism (1.1-1.7 $μ$m) in stare mode. We aimed to further investigate CoRoT-1 b through its secondary eclipses, producing spectrophotometric light curves corrected for charge trapping, also known as the ramp effect in time-series observations with the WFC3. We found that, when correcting for the ramp effect and using the typically discarded first orbit, we are better capable of constraining and optimizing the emission and transmission spectra. We did a grid retrieval in this transitional temperature regime and found the spectra for CoRoT-1 b to be featureless and to agree with an inverted temperature-pressure (T-P) profile. We note, however, that the contribution function for the WFC3 indicates pressures probed near $10^{-3}$ to $10^{0}$ bar, which correspond to a nearly isothermal region in our T-P profile, thereby indicating that the inversion at high altitude is model-dependent. Despite no distinct features, the analysis done on CoRoT-1 b paves the way to high-precision results with stare mode spectroscopy. As a new generation of observations from the James Webb Space Telescope (JWST) approaches, CoRoT-1 b might be an interesting follow-up target because the time-series spectroscopic modes of JWST's NIRSpec, MIRI, and NIRCam instruments will be analogous to HST's stare mode., 18 pages; 12 figures; Astronomical Journal, accepted

Published
2022

18. Hiding in plain sight: observing planet-starspot crossings with the James Webb Space Telescope

Author

Tom J. Wilson, Everett Schlawin, G. Bruno, Jonathan Fraine, Antonino F. Lanza, Joshua D. Lothringer, Gaetano Scandariato, Giuseppina Micela, Nikole K. Lewis, Isabella Pagano, Gianluca Cracchiolo, and Jeff A. Valenti

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, James Webb Space Telescope, Starspot, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stellar classification, Exoplanet, Stars, Wavelength, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Astrophysics::Solar and Stellar Astrophysics, Prism, Astrophysics::Earth and Planetary Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Transiting exoplanets orbiting active stars frequently occult starspots and faculae on the visible stellar disc. Such occultations are often rejected from spectrophotometric transits, as it is assumed they do not contain relevant information for the study of exoplanet atmopsheres. However, they can provide useful constraints to retrieve the temperature of active features and their effect on transmission spectra. We analyse the capabilities of the James Webb Space Telescope in the determination of the spectra of occulted starspots, despite its lack of optical wavelength instruments on board. Focusing on K and M spectral types, we simulate starspots with different temperatures and in different locations of the stellar disc, and find that starspot temperatures can be determined to within a few hundred kelvins using NIRSpec/Prism and the proposed NIRCam/F150W2$+$F322W2's broad wavelength capabilities. Our results are particularly promising in the case of K and M dwarfs of mag$_K \leq 12.5$ with large temperature contrasts., 16 pages, 13 figures, accepted for publication on MNRAS, updated references in Sections 1, 3.1 and 5, updated affiliation details, added link to uploaded material in Data Availability section

Published
2021

19. JWST Noise Floor I: Random Error Sources in JWST NIRCam Time Series

Author

Jarron Leisenring, Michael W. McElwain, Thomas P. Greene, Marcia J. Rieke, Thomas G. Beatty, Everett Schlawin, and Karl Misselt

Subjects
010504 meteorology & atmospheric sciences, Preamplifier, FOS: Physical sciences, 01 natural sciences, law.invention, Optics, law, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Background subtraction, Pixel, business.industry, James Webb Space Telescope, Detector, Astronomy and Astrophysics, Noise floor, Grism, Space and Planetary Science, Resistor, business, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

JWST transmission and emission spectra will provide invaluable glimpses of transiting exoplanet atmospheres, including possible biosignatures. This promising science from JWST, however, will require exquisite precision and understanding of systematic errors that can impact the time series of planets crossing in front of and behind their host stars. Here, we provide estimates of the random noise sources affecting JWST NIRCam time-series data on the integration-to-integration level. We find that 1/f noise can limit the precision of grism time series for 2 groups (230 ppm to 1000 ppm depending on the extraction method and extraction parameters), but will average down like the square root of N frames/reads. The current NIRCam grism time series mode is especially affected by 1/f noise because its GRISMR dispersion direction is parallel to the detector fast-read direction, but could be alleviated in the GRISMC direction. Care should be taken to include as many frames as possible per visit to reduce this 1/f noise source: thus, we recommend the smallest detector subarray sizes one can tolerate, 4 output channels and readout modes that minimize the number of skipped frames (RAPID or BRIGHT2). We also describe a covariance weighting scheme that can significantly lower the contributions from 1/f noise as compared to sum extraction. We evaluate the noise introduced by pre-amplifier offsets, random telegraph noise, and high dark current RC pixels and find that these are correctable below 10 ppm once background subtraction and pixel masking are performed. We explore systematic error sources in a companion paper., Accepted to AJ

Published
2020

20. Eigenspectra: A Framework for Identifying Spectra from 3D Eclipse Mapping

Author

Prashansa Gupta, Jacob Lustig-Yaeger, Y. Katherina Feng, Kevin B. Stevenson, Emily Rauscher, Everett Schlawin, Thomas G. Beatty, Arthur D. Adams, Dylan Keating, Jacob Arcangeli, and Megan Mansfield

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 0303 health sciences, James Webb Space Telescope, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, 03 medical and health sciences, Space and Planetary Science, Planet, Primary (astronomy), 0103 physical sciences, Hot Jupiter, Astrophysics::Earth and Planetary Astrophysics, Longitude, Cluster analysis, 010303 astronomy & astrophysics, 030304 developmental biology, Eclipse, Astrophysics - Earth and Planetary Astrophysics
Abstract

Planetary atmospheres are inherently 3D objects that can have strong gradients in latitude, longitude, and altitude. Secondary eclipse mapping is a powerful way to map the 3D distribution of the atmosphere, but the data can have large correlations and errors in the presence of photon and instrument noise. We develop a technique to mitigate the large uncertainties of eclipse maps by identifying a small number of dominant spectra to make them more tractable for individual analysis via atmospheric retrieval. We use the eigencurves method to infer a multi-wavelength map of a planet from spectroscopic secondary eclipse light curves. We then apply a clustering algorithm to the planet map to identify several regions with similar emergent spectra. We combine the similar spectra together to construct an "eigenspectrum" for each distinct region on the planetary map. We demonstrate how this approach could be used to isolate hot from cold regions and/or regions with different chemical compositions in observations of hot Jupiters with the James Webb Space Telescope (JWST). We find that our method struggles to identify sharp edges in maps with sudden discontinuities, but generally can be used as a first step before a more physically motivated modeling approach to determine the primary features observed on the planet., 13 pages, 17 figures, accepted to MNRAS

Published
2020

21. The Transiting Exoplanet Community Early Release Science Program for JWST

Author

Jacob L. Bean, Kevin B. Stevenson, Natalie M. Batalha, Zachory Berta-Thompson, Laura Kreidberg, Nicolas Crouzet, Björn Benneke, Michael R. Line, David K. Sing, Hannah R. Wakeford, Heather A. Knutson, Eliza M.-R. Kempton, Jean-Michel Désert, Ian Crossfield, Natasha E. Batalha, Julien de Wit, Vivien Parmentier, Joseph Harrington, Julianne I. Moses, Mercedes Lopez-Morales, Munazza K. Alam, Jasmina Blecic, Giovanni Bruno, Aarynn L. Carter, John W. Chapman, Leen Decin, Diana Dragomir, Thomas M. Evans, Jonathan J. Fortney, Jonathan D. Fraine, Peter Gao, Antonio García Muñoz, Neale P. Gibson, Jayesh M. Goyal, Kevin Heng, Renyu Hu, Sarah Kendrew, Brian M. Kilpatrick, Jessica Krick, Pierre-Olivier Lagage, Monika Lendl, Tom Louden, Nikku Madhusudhan, Avi M. Mandell, Megan Mansfield, Erin M. May, Giuseppe Morello, Caroline V. Morley, Nikolay Nikolov, Seth Redfield, Jessica E. Roberts, Everett Schlawin, Jessica J. Spake, Kamen O. Todorov, Angelos Tsiaras, Olivia Venot, William C. Waalkes, Peter J. Wheatley, Robert T. Zellem, Daniel Angerhausen, David Barrado, Ludmila Carone, Sarah L. Casewell, Patricio E. Cubillos, Mario Damiano, Miguel de Val-Borro, Benjamin Drummond, Billy Edwards, Michael Endl, Nestor Espinoza, Kevin France, John E. Gizis, Thomas P. Greene, Thomas K. Henning, Yucian Hong, James G. Ingalls, Nicolas Iro, Patrick G. J. Irwin, Tiffany Kataria, Fred Lahuis, Jérémy Leconte, Jorge Lillo-Box, Stefan Lines, Joshua D. Lothringer, Luigi Mancini, Franck Marchis, Nathan Mayne, Enric Palle, Emily Rauscher, Gaël Roudier, Evgenya L. Shkolnik, John Southworth, Mark R. Swain, Jake Taylor, Johanna Teske, Giovanna Tinetti, Pascal Tremblin, Gregory S. Tucker, Roy van Boekel, Ingo P. Waldmann, Ian C. Weaver, Tiziano Zingales, University of Chicago, Space Telescope Science Institute (STSci), NASA Ames Research Center (ARC), Department of Astrophysical and Planetary Sciences [Boulder], University of Colorado [Boulder], Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Instituto de Astrofisica de Canarias (IAC), Universidad de La Laguna [Tenerife - SP] (ULL), Département de Physique [Montréal], Université de Montréal [Montréal], School of Earth and Space Exploration [Tempe] (SESE), Arizona State University [Tempe] (ASU), University of Exeter, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Grinnell College, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology (MIT), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando], Space Science Institute [Boulder] (SSI), New York University [Abu Dhabi], NYU System (NYU), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), University of California [Santa Cruz] (UCSC), University of California, Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Zentrum für Astronomie und Astrophysik [Berlin] (ZAA), Technische Universität Berlin (TUB), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Center for Space and Habitability (CSH), University of Bern, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Brown University, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Austrian Academy of Sciences (OeAW), University of Warwick [Coventry], Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), GSFC Solar System Exploration Division, NASA Goddard Space Flight Center (GSFC), University of Michigan [Ann Arbor], University of Michigan System, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, The Foundation for Scientific and Industrial Research (SINTEF), College of Engineering, Mathematics and Physical Sciences [Exeter] (EMPS), Wesleyan University, Amsterdam University of Applied Sciences, Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Blue Marble Space Institute of Science (BMSIS), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Physics and Astronomy [Leicester], University of Leicester, Space Research Institute of Austrian Academy of Sciences (IWF), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Astrochemistry Laboratory [Greenbelt], Catholic University of America, McDonald Observatory, University of Texas at Austin [Austin], Center for Astrophysics and Space Astronomy [Boulder] (CASA), Department of Physics and Astronomy [Newark], University of Delaware [Newark], Cornell University, Infrared Processing and Analysis Center (IPAC), University of Vienna [Vienna], Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], SRON Netherlands Institute for Space Research (SRON), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Carl Sagan Center, SETI Institute, Department of Physics, University of Rome Tor Vergata, Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Ames Laboratory [Ames, USA], Iowa State University (ISU)-U.S. Department of Energy (DOE), Low Energy Astrophysics (API, FNWI), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides ( CASSIOPEE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Joseph Louis LAGRANGE ( LAGRANGE ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Observatoire de la Côte d'Azur, Plasmachemistry, CNR-IMIP, Katholieke Universiteit Leuven ( KU Leuven ), University of California [Santa Cruz] ( UCSC ), Eidgenössische Technische Hochschule, Swiss Federal Institute of Technology in Zürich ( ETH Zürich ), Max-Planck-Institut für Astronomie ( MPIA ), Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), The Foundation for Scientific and Industrial Research ( SINTEF ), Laboratoire inter-universitaire des systèmes atmosphèriques ( LISA ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Université Paris-Est Créteil Val-de-Marne - Paris 12 ( UPEC UP12 ) -Centre National de la Recherche Scientifique ( CNRS ), Department of Astrophysical Sciences [Princeton], Princeton University, Center for Astrophysics and Space Astronomy [Boulder] ( CASA ), University of Colorado Boulder [Boulder], Dept of Physics, University of Florida [Gainesville], Stony Brook University [The State University of New York] ( SBU ), ECLIPSE 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] ( LAB ), Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Bordeaux ( UB ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), University College of London [London] ( UCL ), Maison de la Simulation ( MDLS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Paris-Sud - Paris 11 ( UP11 ) -Institut National de Recherche en Informatique et en Automatique ( Inria ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Iowa State University ( ISU ) -U.S. Department of Energy ( DOE ), Université de Montréal (UdeM), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC), Technische Universität Berlin (TU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Stiftelsen for INdustriell og TEknisk Forskning Digital [Trondheim] (SINTEF Digital), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Cornell University [New York], Università degli Studi di Roma Tor Vergata [Roma], Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Iowa State University (ISU)-U.S. Department of Energy [Washington] (DOE), Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Smithsonian Institution-Harvard University [Cambridge], Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Harvard University-Smithsonian Institution, Technical University of Berlin / Technische Universität Berlin (TU), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Agence Spatiale Européenne = European Space Agency (ESA), and University of Oxford

Subjects
MODEL ATMOSPHERES, Exclusive access, 010504 meteorology & atmospheric sciences, Computer science, Science program, observational [methods], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, MIDINFRARED INSTRUMENT, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Planets and satellites: Individual, 01 natural sciences, EXTRASOLAR GIANT PLANETS, Planets and satellites: Atmospheres, individual (WASP-79b, WASP-43b, WASP-18b) [planets and satellites], Settore FIS/05 - Astronomia e Astrofisica, Methods: Observational, Planet, 0103 physical sciences, Early release, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, LIGHT CURVES, Earth and Planetary Astrophysics (astro-ph.EP), Science & Technology, Community engagement, TIME-SERIES PHOTOMETRY, THERMAL EMISSION, James Webb Space Telescope, Astrophysics::Instrumentation and Methods for Astrophysics, WEBB-SPACE-TELESCOPE, Astronomy and Astrophysics, HOT-JUPITER, atmospheres [planets and satellites], [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Data science, Methods observational, Exoplanet, 13. Climate action, Space and Planetary Science, Physical Sciences, HD 189733B, Astrophysics::Earth and Planetary Astrophysics, ATMOSPHERIC CIRCULATION, Astrophysics - Earth and Planetary Astrophysics
Abstract

The James Webb Space Telescope (JWST) presents the opportunity to transform our understanding of planets and the origins of life by revealing the atmospheric compositions, structures, and dynamics of transiting exoplanets in unprecedented detail. However, the high-precision, time-series observations required for such investigations have unique technical challenges, and prior experience with other facilities indicates that there will be a steep learning curve when JWST becomes operational. In this paper we describe the science objectives and detailed plans of the Transiting Exoplanet Community Early Release Science (ERS) Program, which is a recently approved program for JWST observations early in Cycle 1. The goal of this project, for which the obtained data will have no exclusive access period, is to accelerate the acquisition and diffusion of technical expertise for transiting exoplanet observations with JWST, while also providing a compelling set of representative datasets that will enable immediate scientific breakthroughs. The Transiting Exoplanet Community ERS Program will exercise the time-series modes of all four JWST instruments that have been identified as the consensus highest priorities, observe the full suite of transiting planet characterization geometries (transits, eclipses, and phase curves), and target planets with host stars that span an illustrative range of brightnesses. The observations in this program were defined through an inclusive and transparent process that had participation from JWST instrument experts and international leaders in transiting exoplanet studies. Community engagement in the project will be centered on a two-phase Data Challenge that culminates with the delivery of planetary spectra, time-series instrument performance reports, and open-source data analysis toolkits in time to inform the agenda for Cycle 2 of the JWST mission., Comment: PASP in press

Published
2018

22. Spectroscopic characterisation of microlensing events Towards a new interpretation of OGLE-2011-BLG-0417

Author

Nuno C. Santos, J. B. Marquette, Isabelle Boisse, D. P. Bennett, V. Batista, Everett Schlawin, Rodrigo F. Díaz, Pedro Figueira, Jorge Lillo-Box, Terry Herter, David James, J.-P. Beaulieu, B. Rojas Ayala, S. G. Sousa, Alexandre Santerne, Jose-Manuel Almenara, Clément Ranc, Centro de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Departamento de Física e Astronomia [Porto] (DFA/FCUP), Faculdade de Ciências da Universidade do Porto (FCUP), Universidade do Porto = University of Porto-Universidade do Porto = University of Porto, Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Canarias (IAC), Department of Experimental Physics, National University of Ireland Maynooth (Maynooth University), Department of Astronomy [Ithaca], Cornell University [New York], Universidade do Porto, Universidade do Porto-Universidade do Porto, and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Ciencias Físicas, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Gravitational microlensing, 01 natural sciences, purl.org/becyt/ford/1 [https], Bulge, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Spectrograph, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, high angular resolution [techniques], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, purl.org/becyt/ford/1.3 [https], Light curve, Giant star, Radial velocity, Astronomía, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Spectral energy distribution, spectroscopic [techniques], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], individual: OGLE-2011-BLG-0417 [stars], CIENCIAS NATURALES Y EXACTAS, Astrophysics - Earth and Planetary Astrophysics
Abstract

The microlensing event OGLE-2011-BLG-0417 is an exceptionally bright lens binary that was predicted to present radial velocity variation at the level of several km/s. Pioneer radial velocity follow-up observations with the UVES spectrograph at the ESO - VLT of this system clearly ruled out the large radial velocity variation, leaving a discrepancy between the observation and the prediction. In this paper, we further characterise the microlensing system by analysing its spectral energy distribution (SED) derived using the UVES spectrum and new observations with the ARCoIRIS (CTIO) near-infrared spectrograph and the Keck adaptive optics instrument NIRC2 in the J, H, and Ks bands. We determine the mass and distance of the stars independently from the microlensing modelling. We find that the SED is compatible with a giant star in the Galactic bulge and a foreground star with a mass of 0.94+/-0.09Msun at a distance of 1.07+/-0.24kpc. We find that this foreground star is likely the lens. Its parameters are not compatible with the ones previously reported in the literature (0.52+/-0.04Msun at 0.95+/-0.06kpc), based on the microlensing light curve. A thoughtful re-analysis of the microlensing event is mandatory to fully understand the reason of this new discrepancy. More importantly, this paper demonstrates that spectroscopic follow-up observations of microlensing events are possible and provide independent constraints on the parameters of the lens and source stars, hence breaking some degeneracies in the analysis. UV-to-NIR low-resolution spectrographs like X-SHOOTER (ESO - VLT) could substantially contribute to this follow-up efforts, with magnitude limits above all microlensing events detected so far., accepted for publication in A&A Letters

Published
2016

23. Characterizing the Cool KOIs. VI. H- and K-band Spectra of Kepler M Dwarf Planet-candidate Hosts

Author

Ellen M. Price, Bárbara Rojas-Ayala, Christoph Baranec, Rachel Thorp, Juliette C. Becker, Reed Riddle, Kevin R. Covey, James P. Lloyd, Andrew Vanderburg, John Asher Johnson, Everett Schlawin, Nicholas M. Law, Gregory A. Feiden, Philip S. Muirhead, and Katherine Hamren

Subjects
Physics, Dwarf star, 010504 meteorology & atmospheric sciences, Dwarf planet, NASA Exoplanet Archive, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Stellar classification, 01 natural sciences, Spectral line, Stars, Astrophysics - Solar and Stellar Astrophysics, Astronomi, astrofysik och kosmologi, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Visual binary
Abstract

We present H- and K-band spectra for late-type Kepler Objects of Interest (the "Cool KOIs"): low-mass stars with transiting-planet candidates discovered by NASA's Kepler Mission that are listed on the NASA Exoplanet Archive. We acquired spectra of 103 Cool KOIs and used the indices and calibrations of Rojas-Ayala et al. to determine their spectral types, stellar effective temperatures and metallicities, significantly augmenting previously published values. We interpolate our measured effective temperatures and metallicities onto evolutionary isochrones to determine stellar masses, radii, luminosities and distances, assuming the stars have settled onto the main-sequence. As a choice of isochrones, we use a new suite of Dartmouth predictions that reliably include mid-to-late M dwarf stars. We identify five M4V stars: KOI-961 (confirmed as Kepler 42), KOI-2704, KOI-2842, KOI-4290, and the secondary component to visual binary KOI-1725, which we call KOI-1725 B. We also identify a peculiar star, KOI-3497, which has a Na and Ca lines consistent with a dwarf star but CO lines consistent with a giant. Visible-wavelength adaptive optics imaging reveals two objects within a 1 arc second diameter; however, the objects' colors are peculiar. The spectra and properties presented in this paper serve as a resource for prioritizing follow-up observations and planet validation efforts for the Cool KOIs, and are all available for download online using the "data behind the figure" feature., Comment: Accepted for publication in the Astrophysical Journal Supplement Series (ApJS). Data and table are available in the source

Published
2014

24. Characterizing the Cool Kepler Objects of Interest. New Effective Temperatures, Metallicities, Masses and Radii of Low-Mass Kepler Planet-Candidate Host Stars

Author

Bárbara Rojas-Ayala, Everett Schlawin, Kevin R. Covey, Katherine Hamren, James P. Lloyd, and Philip S. Muirhead

Subjects
Physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Kepler, Spectral line, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Planet, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Astrophysics::Earth and Planetary Astrophysics, Low Mass, Circumstellar habitable zone, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

We report stellar parameters for late-K and M-type planet-candidate host stars announced by the Kepler Mission. We obtained medium-resolution, K-band spectra of 84 cool (Teff < 4400 K) Kepler Objects of Interest (KOIs) from Borucki et al. We identified one object as a giant (KOI 977); for the remaining dwarfs, we measured effective temperatures (Teff) and metallicities ([M/H]) using the K-band spectral indices of Rojas-Ayala et al. We determine the masses and radii of the cool KOIs by interpolation onto the Dartmouth evolutionary isochrones. The resultant stellar radii are significantly less than the values reported in the Kepler Input Catalogue and, by construction, correlate better with Teff. Applying the published KOI transit parameters to our stellar radius measurements, we report new physical radii for the planet candidates. Recalculating the equilibrium temperatures of the planet-candidates assuming Earth's albedo and re-radiation fraction, we find that 3 of the planet-candidates are terrestrial-sized with orbital semi-major axes that lie within the habitable zones of their host stars (KOI 463.01, KOI 812.03 and KOI 854.01). The stellar parameters presented in this letter serve as a resource for prioritization of future follow-up efforts to validate and characterize the cool KOI planet candidates., Published in ApJ Letters. We now interpolate measured Teff and [M/H] onto Dartmouth isochrones (originally used Padova in v1), and include method verification on nearby stars (see new Figure 3). Machine readable table is available in the source code

Published
2011

26. Infrared Variability of Two Dusty White Dwarfs.

Author

Siyi Xu, Kate Y. L. Su, L. K. Rogers, Amy Bonsor, Johan Olofsson, Dimitri Veras, Rik van Lieshout, Patrick Dufour, Elizabeth M. Green, Everett Schlawin, Jay Farihi, Thomas G. Wilson, David J. Wilson, and Boris T. Gänsicke

Subjects
WHITE dwarf stars, INFRARED radiation, CIRCUMSTELLAR matter, ASTEROIDS, PLANETESIMALS
Abstract

The most heavily polluted white dwarfs often show excess infrared radiation from circumstellar dust disks, which are modeled as a result of tidal disruption of extrasolar minor planets. Interaction of dust, gas, and disintegrating objects can all contribute to the dynamical evolution of these dust disks. Here, we report two infrared variable dusty white dwarfs, SDSS J1228+1040 and G29-38. For SDSS J1228+1040, compared to the first measurements in 2007, the IRAC [3.6] and [4.5] fluxes decreased by 20% before 2014 to a level also seen in the recent 2018 observations. For G29-38, the infrared flux of the 10 μm silicate emission feature became 10% stronger between 2004 and 2007, We explore several scenarios that could account for these changes, including tidal disruption events, perturbation from a companion, and runaway accretion. No satisfactory causes are found for the flux drop in SDSS J1228+1040 due to the limited time coverage. Continuous tidal disruption of small planetesimals could increase the mass of small grains and concurrently change the strength of the 10 μm feature of G29-38. Dust disks around white dwarfs are actively evolving and we speculate that there could be different mechanisms responsible for the temporal changes of these disks. [ABSTRACT FROM AUTHOR]

Published
2018
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28. Transiting Exoplanet Studies and Community Targets for JWST 's Early Release Science Program

Author

Jonathan J. Fortney, Jonathan Fraine, Tiffany Kataria, Kevin Heng, Heather A. Knutson, Nicolas Crouzet, Caroline V. Morley, Joanna K. Barstow, Brian M. Kilpatrick, Gregory S. Tucker, Charles A. Beichman, Eric Agol, David K. Sing, Nicolas B. Cowan, David Ehrenreich, Thomas P. Greene, David Charbonneau, Michael R. Line, Drake Deming, Shannon Curry, Nikku Madhusudhan, Kamen O. Todorov, Jessica Krick, Hannah R. Wakeford, Adam Burrows, Marco Rocchetto, David Lafrenière, Everett Schlawin, Joseph Harrington, John E. Gizis, Avi Shporer, Patricio E. Cubillos, Stephan M. Birkmann, Nikole K. Lewis, Diana Dragomir, Paul A. Dalba, Jeff A. Valenti, Laura Kreidberg, Evgenya L. Shkolnik, Avi Mandell, Neale P. Gibson, Kevin B. Stevenson, Antonio García Muñoz, Jean-Michel Desert, Mercedes Lopez-Morales, Julien de Wit, Jacob L. Bean, Daniel Angerhausen, Joshua D. Lothringer, Eliza M.-R. Kempton, René Doyon, Pierre Olivier Lagage, and Low Energy Astrophysics (API, FNWI)

Subjects
Brightness, 010504 meteorology & atmospheric sciences, Computer science, Science program, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 01 natural sciences, 0103 physical sciences, Spectral resolution, Early release, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), James Webb Space Telescope, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, telescopes, atmospheres [planets and satellites], Exoplanet, 3. Good health, Space and Planetary Science, individual [planets and satellites], astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astronomical and Space Sciences, Astrophysics - Earth and Planetary Astrophysics, astro-ph.IM
Abstract

The James Webb Space Telescope will revolutionize transiting exoplanet atmospheric science due to its capability for continuous, long-duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful future transiting exoplanet characterization programs. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed "community targets") that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations.(Abridged), This is a white paper that originated from an open discussion at the Enabling Transiting Exoplanet Science with JWST workshop held November 16 - 18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted for publication in PASP

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