Confirmation of an He I evaporating atmosphere around the 650-Myr-old sub-Neptune HD 235088 b (TOI-1430 b) with CARMENES

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Authors and Corporations:

Orell-Miquel, Jaume (Author), Lampón, Manuel (Author), López-Puertas, M. (Author), Mallorquín, Manuel (Author), Murgas, F. (Author), Peláez-Torres, A. (Author), Pallé, Enric (Author), Esparza-Borges, Emma (Author), Sanz-Forcada, J. (Author), Tabernero, H. M. (Author), Nortmann, Lisa (Author), Nagel, E. (Author), Parviainen, H. (Author), Zapatero Osorio, Maria Rosa (Author), Caballero, José A. (Author), Czesla, S. (Author), Cifuentes, C. (Author), Morello, G. (Author), Quirrenbach, Andreas (Author), Amado, P. J. (Author), Fernández-Martín, A. (Author), Fukui, A. (Author), Henning, Thomas (Author), Kawauchi, K. (Author), Leon, J. P. de (Author), Molaverdikhani, Karan (Author), Montes, D. (Author), Narita, N. (Author), Reiners, A. (Author), Ribas, I. (Author), Sánchez-López, A. (Author), Schweitzer, A. (Author), Stangret, M. (Author), Yan, F. (Author)

Other Authors:

Lampón, Manuel [Author] • López-Puertas, M. [Author] • Mallorquín, Manuel [Author] • Murgas, F. [Author] • Peláez-Torres, A. [Author] • Pallé, Enric [Author] • Esparza-Borges, Emma [Author] • Sanz-Forcada, J. [Author] • Tabernero, H. M. [Author] • Nortmann, Lisa [Author] • Nagel, E. [Author] • Parviainen, H. [Author] • Zapatero Osorio, Maria Rosa [Author] • Caballero, José A. 1977- [Author] • Czesla, S. [Author] • Cifuentes, C. [Author] • Morello, G. [Author] • Quirrenbach, Andreas [Author] • Amado, P. J. [Author] • Fernández-Martín, A. [Author] • Fukui, A. [Author] • Henning, Thomas 1956- [Author] • Kawauchi, K. [Author] • Leon, J. P. de [Author] • Molaverdikhani, Karan 1982- [Author] • Montes, D. [Author] • Narita, N. [Author] • Reiners, A. [Author] • Ribas, I. [Author] • Sánchez-López, A. [Author] • Schweitzer, A. [Author] • Stangret, M. [Author] • Yan, F. [Author]

Type of Resource:

E-Book Component Part

Language:

English

published:

September 2023

Series:

Astronomy and astrophysics, 677(2023) vom: Sept., Artikel-ID A56, Seite 1-17

Source:

Verbunddaten SWB
Lizenzfreie Online-Ressourcen

ISSN:

1432-0746

Description
Summary:	HD 235088 (TOI-1430) is a young star known to host a sub-Neptune-sized planet candidate. We validated the planetary nature of HD 235088 b with multiband photometry, refined its planetary parameters, and obtained a new age estimate of the host star, placing it at 600-800 Myr. Previous spectroscopic observations of a single transit detected an excess absorption of He I coincident in time with the planet candidate transit. Here, we confirm the presence of He I in the atmosphere of HD 235088 b with one transit observed with CARMENES. We also detected hints of variability in the strength of the helium signal, with an absorption of −0.91 ± 0.11%, which is slightly deeper (2<i>σ<i/>) than the previous measurement. Furthermore, we simulated the He I signal with a spherically symmetric 1D hydrodynamic model, finding that the upper atmosphere of HD 235088 b escapes hydrodynamically with a significant mass loss rate of (1.5−5) × 10<sup>10<sup/> g s<sup>−1<sup/> in a relatively cold outflow, with <i>T<i/> = 3125 ±375 K, in the photon-limited escape regime. HD 235088 b (<i>R<i/><sub>p<sub/> = 2.045 ± 0.075 <i>R<i/><sub>⊕<sub/>) is the smallest planet found to date with a solid atmospheric detection - not just of He I but any other atom or molecule. This positions it a benchmark planet for further analyses of evolving young sub-Neptune atmospheres.
Item Description:	Gesehen am 23.04.2024 Online veröffentlicht: 05. September 2023
Physical Description:	Illustrationen 17
ISSN:	1432-0746
DOI:	10.1051/0004-6361/202346445