Evidence of energy-, recombination-, and photon-limited escape regimes in giant planet H/He atmospheres

DOI: 
10.1051/0004-6361/202140423
Publication date: 
24/04/2021
Main author: 
Lampón, M.
IAA authors: 
Lampón, M.;López-Puertas, M.;Lara, L. M.;Amado, P. J.
Authors: 
Lampón, M.;López-Puertas, M.;Czesla, S.;Sánchez-López, A.;Lara, L. M.;Salz, M.;Sanz-Forcada, J.;Molaverdikhani, K.;Quirrenbach, A.;Pallé, E.;Caballero, J. A.;Henning, Th.;Nortmann, L.;Amado, P. J.;Montes, D.;Reiners, A.;Ribas, I.
Journal: 
Astronomy and Astrophysics
Refereed: 
Yes
Publication type: 
Article
Volume: 
648
Pages: 
L7
Abstract: 
Hydrodynamic escape is the most efficient atmospheric mechanism of planetary mass loss and has a large impact on planetary evolution. Three hydrodynamic escape regimes have been identified theoretically: energy-limited, recombination-limited, and photon-limited. However, no evidence of these regimes had been reported until now. Here, we report evidence of these three regimes via an analysis of a helium I triplet at 10 830 Å and Lyα absorption involving a 1D hydrodynamic model that allows us to estimate hydrogen recombination and advection rates. In particular, we show that HD 209458 b is in the energy-limited regime, HD 189733 b is in the recombination-limited regime, and GJ 3470 b is in the photon-limited regime. These exoplanets can be considered as benchmark cases for their respective regimes.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2021A&A...648L...7L/abstract
ADS Bibcode: 
2021A&A...648L...7L
Keywords: 
planets and satellites: atmospheres;planets and satellites: gaseous planets;planets and satellites: individual: GJ 3470 b;planets and satellites: individual: HD 209458 b;planets and satellites: individual: HD 189733 b;Astrophysics - Earth and Planetary Astrophysics