The overflowing atmosphere of WASP-121 b: High-resolution He I λ10833 transmission spectroscopy with VLT/CRIRES+

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 λ10833 triplet lines. Our analysis shows...

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Bibliographic Details
Authors: Czesla, S., Nail, F., Lavail, A., Cont, David, Nortmann, L., Lesjak, Fabio, Rengel, M., Boldt-Christmas, L., Shulyak, D., Seemann, U., Schneider, P. Christian, Hatzes, Artie P., Kochukhov, O., Piskunov, N., Reiners, Ansgar, Wilson, D. J., Yan, F.
Format: article
Status:Published version
Publication Date:2024
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/375529
Online Access:http://hdl.handle.net/10261/375529
Access Level:Open access
Keyword:Techniques: spectroscopic
Planets and satellites: atmospheres
Planets and satellites: individual: WASP-121
X-rays: stars
Description
Summary: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 λ10833 triplet lines. Our analysis shows a prominent He I λ10833 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 × 1013 g s−1 for the stellar and 5.4 × 1012 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. © The Authors 2024

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