The overflowing atmosphere of WASP-121 b
Transmission spectroscopy is a prime method to study the atmospheres of extrasolar planets. We obtained a high-resolution spectral transit time series of the hot Jupiter WASP-121 b with CRIRES+ to study its atmosphere via transmission spectroscopy of the He I λ 10833 triplet lines. Our analysis shows a prominent He I λ 10833 absorption feature moving along with the planetary orbital motion, which shows an observed, transit-averaged equivalent width of approximately 30 mÅ, a slight redshift, and a depth of about 2%, which can only be explained by an atmosphere overflowing its Roche lobe. We carried out 3D hydrodynamic modeling to reproduce the observations, which favors asymmetric mass loss with a more pronounced leading tidal tail, possibly also explaining observational evidence for additional absorption stationary in the stellar rest frame. A trailing tail is not detectable. From our modeling, we derived estimates of ≥2 × 10 13 g s −1 for the stellar and 5.4 × 10 12 g s −1 for the planetary mass loss rate, which is consistent with X-ray and extreme-ultraviolet (XUV) driven mass loss in WASP-121 b.
Authors
- F. Lesjak (ORCID: https://orcid.org/0000-0001-6082-1175)
- D. Cont (ORCID: https://orcid.org/0000-0002-6187-8154)
- L. Nortmann (ORCID: https://orcid.org/0000-0001-8419-8760)
- D. Shulyak (ORCID: https://orcid.org/0000-0001-8496-2482)
- A. P. Hatzes (ORCID: https://orcid.org/0000-0002-3404-8358)
- O. Kochukhov (ORCID: https://orcid.org/0000-0003-3061-4591)
- A. Lavail (ORCID: https://orcid.org/0000-0001-8477-5265)
- F. Yan
- L. Boldt-Christmas (ORCID: https://orcid.org/0000-0003-1739-3827)
- P. C. Schneider (ORCID: https://orcid.org/0000-0002-5094-2245)
- Nikolai E. Piskunov (ORCID: https://orcid.org/0000-0001-5742-7767)
- M. Rengel (ORCID: https://orcid.org/0000-0001-6419-4893)
- U. Seemann
- F. Nail (ORCID: https://orcid.org/0009-0008-4762-6170)
- A. Reiners
- D. J. Wilson
- S. Czesla
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2024-11-26
- DOI
- https://doi.org/10.1051/0004-6361/202451003
- Citations
- 2
- Primary Topic
- Atmospheric Ozone and Climate
- Type
- article
- Field-Weighted Citation Impact
- 0.75
Funders
- National Aeronautics and Space Administration
- California Institute of Technology
- Deutsche Forschungsgemeinschaft
- National Natural Science Foundation of China
- Knut och Alice Wallenbergs Stiftelse
- Agencia Estatal de Investigación