Europlanet Science Congress 2021
Virtual meeting
13 – 24 September 2021
Europlanet Science Congress 2021
Virtual meeting
13 September – 24 September 2021
EPSC Abstracts
Vol. 15, EPSC2021-413, 2021
European Planetary Science Congress 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Characterisation of the hydrodynamic atmospheric escape of HD 209458 b, HD 189733 b, and GJ 3470 b

Manuel Lampón1, Manuel López-Puertas1, Alejandro Sánchez-López2, Stefan Czesla3, Jorge Sanz-Forcada4, and the CARMENES Consortium*
Manuel Lampón et al.
  • 1Instituto de Astrofísica de Andalucía, CSIC, Granada, Spain (
  • 2Leiden Observatory, Leiden University, Postbus 9513, 2300 RA, Leiden, The Netherlands
  • 3Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
  • 4Centro de Astrobiología (CSIC-INTA), ESAC, Camino bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
  • *A full list of authors appears at the end of the abstract

Hydrodynamic escape is the most efficient atmospheric mechanism of planetary mass loss and has a large impact on planetary evolution. However, the lack of observations remained this mechanism poorly understood. Therefore, new observations of the He I triplet at 10830 Å provide key information to advance hydrodynamic escape knowledge. In this work, we analyse the hydrodynamic escape of three exoplanets, HD209458 b, HD189733 b, and GJ 3470 b via an analysis of He triplet absorptions recently observed by the CARMENES high-resolution spectrograph, and their available Ly-alpha measurements, involving a 1D hydrodynamic model. We characterise the main upper atmospheric parameters, e.g.,  the temperature, the composition (H/He ratio), and the radial outflow velocity. We also study their hydrodynamic regime and show that HD209458 b is in the energy-limited regime, HD189733 b is in the recombination-limited regime, and GJ 3470 b is in the photon-limited regime. Details of this work can be found in [1], [2], [3].


[1] Lampón, M., López-Puertas, M., Lara, L.M., et al. 2020, A&A, 636, A13
[2] Lampón, M., López-Puertas, M., Sanz-Forcada, J., et al. 2021, A&A, 647, A129
[3] Lampón, M., López-Puertas, M., Czesla, S., et al. 2021, A&A, 648, L7

CARMENES Consortium:

K. Molaverdikhani, A. Quirrenbach, E. Pallé, J. A. Caballero, Th. Henning, L. Nortmann, P. J. Amado, D. Montes, A. Reiners, and I. Ribas.

How to cite: Lampón, M., López-Puertas, M., Sánchez-López, A., Czesla, S., and Sanz-Forcada, J. and the CARMENES Consortium: Characterisation of the hydrodynamic atmospheric escape of HD 209458 b, HD 189733 b, and GJ 3470 b, European Planetary Science Congress 2021, online, 13–24 Sep 2021, EPSC2021-413,, 2021.

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