JWST NIRSpec finds no clear signs of an atmosphere on TOI-1685 b
Chloe E. Fisher, Matthew J. Hooton, Am\'elie Gressier, Merlin Zgraggen, Meng Tian, Kevin Heng, Natalie H. Allen, Richard D. Chatterjee, Brett M. Morris, Nicholas W. Borsato, N\'estor Espinoza, Daniel Kitzmann, Tobias G. Meier, Lars A. Buchhave, Adam J. Burgasser

TL;DR
This study used JWST NIRSpec observations to investigate the atmosphere of the terrestrial exoplanet TOI-1685 b, finding no evidence of an atmosphere and setting constraints on possible atmospheric compositions, highlighting detection challenges.
Contribution
First detailed JWST NIRSpec analysis of TOI-1685 b, establishing the absence of a hydrogen-dominated atmosphere and constraining the mean molecular weight of potential secondary atmospheres.
Findings
No evidence for an atmosphere based on Bayesian analysis.
Hydrogen-dominated atmospheres are confidently ruled out.
Heavy secondary atmospheres with mean molecular weight ~10 are possible.
Abstract
Determining the prevalence of atmospheres on terrestrial planets is a core objective in exoplanetary science. While M dwarf systems offer a promising opportunity, conclusive observations of terrestrial atmospheres have remained elusive, with many yielding flat transmission spectra. We observe four transits of the hot terrestrial planet TOI-1685 b using JWST's NIRSpec G395H instrument. Combining this with the transit from the previously-observed phase curve of the planet with the same instrument, we perform a detailed analysis to determine the possibility of an atmosphere on TOI-1685 b. From our retrievals, the Bayesian evidence favours a simple flat line model, indicating no evidence for an atmosphere on TOI-1685 b, in line with results from the phase curve analysis. Our results show that hydrogen-dominated atmospheres can be confidently ruled out. For heavier, secondary atmospheres we…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
Taxonomy
TopicsStellar, planetary, and galactic studies · Astronomy and Astrophysical Research · Astrophysics and Star Formation Studies
