Effects of charge exchange on the evaporative wind of HD 209458b
ABSTRACT The role of charge exchange in shaping exoplanet photoevaporation remains a topic of contention. Exchange of electrons between stellar wind protons from the exoplanet’s host star and neutral hydrogen from the planet’s wind has been proposed as a mechanism to create ‘energetic neutral atoms’ (ENAs), which could explain the high absorption line velocities observed in systems where mass-loss is occurring. In this paper, we present results from three-dimensional hydrodynamic simulations of the mass-loss of a planet similar to HD 209458b. We self-consistently launch a planetary wind by calculating the ionization and heating resulting from incident high-energy radiation, inject a stellar wind into the simulation, and allow electron exchange between the stellar and planetary winds. We predict the potential production of ENAs by the wind–wind interaction analytically, and then present the results of our simulations, which confirm the analytic limits. Within the limits of our hydrodynamic simulation, we find that charge exchange with the stellar wind properties examined here is unable to explain the absorption observed at high Doppler velocities.
- Research Organization:
- University of Rochester, NY (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); Space Telescope Science Institute; USDOE
- Grant/Contract Number:
- SC0001063; SC0020432; SC0020434
- OSTI ID:
- 1892108
- Journal Information:
- Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 2 Vol. 517; ISSN 0035-8711
- Publisher:
- Oxford University PressCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
Similar Records
ENERGETIC NEUTRAL ATOMS AROUND HD 209458b: ESTIMATIONS OF MAGNETOSPHERIC PROPERTIES
Ly α Absorption at Transits of HD 209458b: A Comparative Study of Various Mechanisms Under Different Conditions