_version_ 1866915661395001344
author Allen, Natalie H.
Espinoza, Néstor
Boehm, V. A.
Cañas, Caleb I.
Stevenson, Kevin B.
Lewis, Nikole K.
MacDonald, Ryan J.
Morris, Brett M.
Agol, Eric
Colón, Knicole
Diamond-Lowe, Hannah
Glidden, Ana
Gressier, Amélie
Huang, Jingcheng
Lin, Zifan
Long, Douglas
Louie, Dana R.
MacGregor, Meredith A.
Pueyo, Laurent
Rackham, Benjamin V.
Ranjan, Sukrit
Seager, Sara
Mendoza, Guadalupe Tovar
Valenti, Jeff A.
Valentine, Daniel
van der Marel, Roeland P.
Wakeford, Hannah R.
author_facet Allen, Natalie H.
Espinoza, Néstor
Boehm, V. A.
Cañas, Caleb I.
Stevenson, Kevin B.
Lewis, Nikole K.
MacDonald, Ryan J.
Morris, Brett M.
Agol, Eric
Colón, Knicole
Diamond-Lowe, Hannah
Glidden, Ana
Gressier, Amélie
Huang, Jingcheng
Lin, Zifan
Long, Douglas
Louie, Dana R.
MacGregor, Meredith A.
Pueyo, Laurent
Rackham, Benjamin V.
Ranjan, Sukrit
Seager, Sara
Mendoza, Guadalupe Tovar
Valenti, Jeff A.
Valentine, Daniel
van der Marel, Roeland P.
Wakeford, Hannah R.
contents One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST transit observations of the TRAPPIST-1 planets show significant contamination from stellar surface features that we are unable to confidently model. Here, we present the motivation and first observations of our JWST multi-cycle program of TRAPPIST-1 e, which utilize close transits of the airless TRAPPIST-1 b to model-independently correct for stellar contamination, with the goal of determining whether TRAPPIST-1 e has an Earth-like mean molecular weight atmosphere containing CO$_2$. We present our simulations, which show that with the 15 close transit observations, we will be able to detect this atmosphere on TRAPPIST-1 e at $Δ\ln\,Z=5$ or greater confidence assuming we are able to correct for stellar contamination using the close transit observations. We also show the first three observations of our program. We find that our ability to correct for stellar contamination can be inhibited when strong stellar flares are present, as flares can break the assumption that the star does not change meaningfully between planetary transits. The cleanest observation demonstrates the removal of stellar contamination contribution through an increased preference for a flat line over the original TRAPPIST-1 e spectrum, but highlights how minor data analysis assumptions can propagate significantly when searching for small atmospheric signals. This is amplified when using the signals from multiple planets, which is important to consider as we continue our atmospheric search.
format Preprint
id arxiv_https___arxiv_org_abs_2512_07695
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle JWST TRAPPIST-1 e/b Program: Motivation and first observations
Allen, Natalie H.
Espinoza, Néstor
Boehm, V. A.
Cañas, Caleb I.
Stevenson, Kevin B.
Lewis, Nikole K.
MacDonald, Ryan J.
Morris, Brett M.
Agol, Eric
Colón, Knicole
Diamond-Lowe, Hannah
Glidden, Ana
Gressier, Amélie
Huang, Jingcheng
Lin, Zifan
Long, Douglas
Louie, Dana R.
MacGregor, Meredith A.
Pueyo, Laurent
Rackham, Benjamin V.
Ranjan, Sukrit
Seager, Sara
Mendoza, Guadalupe Tovar
Valenti, Jeff A.
Valentine, Daniel
van der Marel, Roeland P.
Wakeford, Hannah R.
Earth and Planetary Astrophysics
One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so is TRAPPIST-1. However, JWST transit observations of the TRAPPIST-1 planets show significant contamination from stellar surface features that we are unable to confidently model. Here, we present the motivation and first observations of our JWST multi-cycle program of TRAPPIST-1 e, which utilize close transits of the airless TRAPPIST-1 b to model-independently correct for stellar contamination, with the goal of determining whether TRAPPIST-1 e has an Earth-like mean molecular weight atmosphere containing CO$_2$. We present our simulations, which show that with the 15 close transit observations, we will be able to detect this atmosphere on TRAPPIST-1 e at $Δ\ln\,Z=5$ or greater confidence assuming we are able to correct for stellar contamination using the close transit observations. We also show the first three observations of our program. We find that our ability to correct for stellar contamination can be inhibited when strong stellar flares are present, as flares can break the assumption that the star does not change meaningfully between planetary transits. The cleanest observation demonstrates the removal of stellar contamination contribution through an increased preference for a flat line over the original TRAPPIST-1 e spectrum, but highlights how minor data analysis assumptions can propagate significantly when searching for small atmospheric signals. This is amplified when using the signals from multiple planets, which is important to consider as we continue our atmospheric search.
title JWST TRAPPIST-1 e/b Program: Motivation and first observations
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2512.07695