English

JWST-TST DREAMS: Secondary Atmosphere Constraints for the Habitable Zone Planet TRAPPIST-1 e

Earth and Planetary Astrophysics 2025-09-09 v1

Abstract

The TRAPPIST-1 system offers one of the best opportunities to characterize temperate terrestrial planets beyond our own solar system. Within the TRAPPIST-1 system, planet e stands out as highly likely to sustain surface liquid water if it possesses an atmosphere. Recently, we reported the first JWST/NIRSpec PRISM transmission spectra of TRAPPIST-1 e, revealing significant stellar contamination, which varied between the four visits. Here, we assess the range of planetary atmospheres consistent with our transmission spectrum. We explore a wide range of atmospheric scenarios via a hierarchy of forward modeling and retrievals. We do not obtain strong evidence for or against an atmosphere. Our results weakly disfavor CO2_2-rich atmospheres for pressures corresponding to the surface of Venus and Mars and the cloud tops of Venus at 2σ\sigma. We exclude H2_2-rich atmospheres containing CO2_2 and CH4_4 in agreement with past work, but find that higher mean molecular weight, N2_2-rich atmospheres with trace CO2_2 and CH4_4 are permitted by the data. Both a bare rock and N2_2-rich atmospheric scenario provide adequate fits to the data, but do not fully explain all features, which may be due to either uncorrected stellar contamination or atmospheric signals. Ongoing JWST observations of TRAPPIST-1 e, exploiting consecutive transits with TRAPPIST-1 b, will offer stronger constraints via a more effective stellar contamination correction. The present work is part of the JWST Telescope Scientist Team (JWST-TST) Guaranteed Time Observations, which is performing a Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).

Keywords

Cite

@article{arxiv.2509.05407,
  title  = {JWST-TST DREAMS: Secondary Atmosphere Constraints for the Habitable Zone Planet TRAPPIST-1 e},
  author = {Ana Glidden and Sukrit Ranjan and Sara Seager and Néstor Espinoza and Ryan J. MacDonald and Natalie H. Allen and Caleb I. Cañas and David Grant and Amélie Gressier and Kevin B. Stevenson and Natasha E. Batalha and Nikole K. Lewis and Douglas Long and Hannah R. Wakeford and Lili Alderson and Ryan C. Challener and Knicole Colón and Jingcheng Huang and Zifan Lin and Dana R. Louie and Elijah Mullens and Kristin S. Sotzen and Jeff A. Valenti and Daniel Valentine and Mark Clampin and C. Matt Mountain and Marshall Perrin and Roeland P. van der Marel},
  journal= {arXiv preprint arXiv:2509.05407},
  year   = {2025}
}

Comments

29 pages, 8 figures, accepted for publication in ApJL