Two regimes of interaction of a Hot Jupiter's escaping atmosphere with the stellar wind and generation of energized atomic hydrogen corona

Abstract

The interaction of escaping upper atmosphere of a hydrogen rich non-magnetized analog of HD209458b with a stellar wind of its host G-type star at different orbital distances is simulated with a 2D axisymmetric multi-fluid hydrodynamic model. A realistic sun-like spectrum of XUV radiation which ionizes and heats the planetary atmosphere, hydrogen photo-chemistry, as well as stellar-planetary tidal interaction are taken into account to generate self-consistently an atmospheric hydrodynamic outflow. Two different regimes of the planetary and stellar winds interaction have been modelled. These are: 1) the "captured by the star" regime, when the tidal force and pressure gradient drive the planetary material beyond the Roche lobe towards the star, and 2) the "blown by the wind" regime, when sufficiently strong stellar wind confines the escaping planetary atmosphere and channels it into the tail. The model simulates in details the hydrodynamic interaction between the planetary atoms, protons and the stellar wind, as well as the production of energetic neutral atoms (ENAs) around the planet due to charge-exchange between planetary atoms and stellar protons. The revealed location and shape of the ENA cloud either as a paraboloid shell between ionopause and bowshock (for the "blown by the wind" regime), or a turbulent layer at the contact boundary between the planetary stream and stellar wind (for the "captured by the star" regime) are of importance for the interpretation of Lyα absorption features in exoplanetary transit spectra and characterization of the plasma environments.

Published on ApJ

References in corpus (16)

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Cited by in corpus (6)

• Hubble PanCET: An extended upper atmosphere of neutral hydrogen around the warm Neptune GJ 3470 b
• Global 3D hydrodynamic modeling of in-transit Lyα absorption of GJ436b
• Lyα Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions
• Effect of stellar wind induced magnetic fields on planetary obstacles of non-magnetized hot Jupiters
• Hydrodynamical interaction of stellar and planetary winds: effects of charge exchange and radiation pressure on the observed Ly$\alpha$ absorption
• Transit Ly-$\alpha$ signatures of terrestrial planets in the habitable zones of M dwarfs