Early Release Science Of The Exoplanet WASP-39b With JWST NIRISS

Early publication of the science of exoplanet WASP-39b with JWST NIRISS – Astrobiology

Interpretation of the components of the transmission spectrum of NIRISS WASP-39b. (a/b): The upper image shows the comparison of the transmission spectrum of WASP-39b from nirHiss reduction (grey dots) with respect to the best-fit reference model (black line). Each colored line removes a key component found in our best-fit reference model to show how the spectrum would change if those features were not included. Removal of clouds and H2O absorption from the reference model lead to large-scale changes in the shape and depth of the transmission spectrum. Other sources of turbidity affecting the spectrum are K, CO and CO2. Residuals between the data and the reference model are shown below. (c/d): The two lower panels show the molecular absorption cross sections for a selection of observable gases within the NIRISS bandpass. The center panel highlights gases derived from our analysis of the spectrum of WASP-39b. The lower panel highlights some gases not identified in this data but which may be present in future observations of other exoplanets. (https://github.com/afeinstein20/wasp39b_niriss_paper/blob/main/scripts/figure3.py) – astro-ph.EP

Transmission spectroscopy provides insight into the atmospheric properties and thus into the history of formation, physics and chemistry of passing exoplanets. However, in order to draw accurate inferences about atmospheric properties from transmission spectra, it is necessary to simultaneously measure the strength and shape of multiple spectral absorption features of a variety of chemical species.

Given the precision and wavelength coverage of previous observatories, this was a challenge. Here we present the transmission spectrum of the Saturn-mass exoplanet WASP-39b obtained with the SOSS mode of the NIRISS instrument at JWST.

This spectrum spans a wavelength from 0.6 to 2.8 μm and shows several water absorption bands, the potassium resonance doublet, and cloud signatures. The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracy between cloud properties and the atmospheric composition of WASP-39b, favoring a heavy element (“metallicity”) enhancement of ∼10−30× the solar value, a sub -Solar carbon-to-oxygen (C/O) ratio and a solar to supersolar potassium-to-oxygen (K/O) ratio.

The observations are best explained by wavelength-dependent, non-grey clouds with inhomogeneous coverage of the planet’s terminator.

Adina D Feinstein, Michael Radica, Luis Welbanks, Catriona Anne Murray, Kazumasa Ohno, Louis-Philippe Coulombe, Néstor Espinoza, Jacob L Bean, Johanna K Teske, Bjorn 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, SL Casewell, Katy L Chubb, Ian JM Crossfield, Nicolas Crouzet, Patricio E Cubillos, Leen D ecin, 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, EM May, NJ Mayne, Nikolay K. Nikolov, Enric Palle, Dominique JM 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

Commentary: 48 pages, 12 figures, 2 tables. Will be verified at Nature
Subjects: Astrophysics of the Earth and Planets (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2211.10493 [astro-ph.EP] (or arXiv:2211.10493v1 [astro-ph.EP] for this version)
Submission History
By: Adina Feinstein
[v1] Friday, November 18, 2022 20:01:34 UTC (7,388 KB)

#Early #publication #science #exoplanet #WASP39b #JWST #NIRISS #Astrobiology

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