Atmospheric escape by magnetically driven wind from gaseous planets
Abstract
We calculate the mass loss driven by magnetohydrodynamic (MHD) waves from hot Jupiters by using MHD simulations in one-dimensional flux tubes. If a gaseous planet has a magnetic field, MHD waves are excited by turbulence at the surface, dissipate in the upper atmosphere, and drive gas outflows. Our calculation shows that mass-loss rates are comparable to the observed mass-loss rates of hot Jupiters; therefore, it is suggested that gas flow driven by MHD waves can play an important role in the mass loss from gaseous planets. The mass-loss rate varies dramatically with the radius and mass of a planet: a gaseous planet with a small mass but an inflated radius produces a very large mass-loss rate. We also derive an analytical expression for the dependence of mass-loss rate on planet radius and mass that is in good agreement with the numerical calculation. The mass-loss rate also depends on the amplitude of the velocity dispersion at the surface of a planet. Thus, we expect to infer the condition of the surface and the internal structure of a gaseous planet from future observations of mass-loss rate from various exoplanets.
- Authors:
-
- Department of Physics, Nagoya University, Nagoya, Aichi 464-8602 (Japan)
- Publication Date:
- OSTI Identifier:
- 22365227
- Resource Type:
- Journal Article
- Journal Name:
- Astrophysical Journal
- Additional Journal Information:
- Journal Volume: 792; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; COMPARATIVE EVALUATIONS; DISPERSIONS; GAS FLOW; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MASS TRANSFER; SATELLITE ATMOSPHERES; SATELLITES; SIMULATION; STELLAR WINDS; SURFACES; TURBULENCE; VELOCITY
Citation Formats
Tanaka, Yuki A., Suzuki, Takeru K., and Inutsuka, Shu-ichiro. Atmospheric escape by magnetically driven wind from gaseous planets. United States: N. p., 2014.
Web. doi:10.1088/0004-637X/792/1/18.
Tanaka, Yuki A., Suzuki, Takeru K., & Inutsuka, Shu-ichiro. Atmospheric escape by magnetically driven wind from gaseous planets. United States. https://doi.org/10.1088/0004-637X/792/1/18
Tanaka, Yuki A., Suzuki, Takeru K., and Inutsuka, Shu-ichiro. 2014.
"Atmospheric escape by magnetically driven wind from gaseous planets". United States. https://doi.org/10.1088/0004-637X/792/1/18.
@article{osti_22365227,
title = {Atmospheric escape by magnetically driven wind from gaseous planets},
author = {Tanaka, Yuki A. and Suzuki, Takeru K. and Inutsuka, Shu-ichiro},
abstractNote = {We calculate the mass loss driven by magnetohydrodynamic (MHD) waves from hot Jupiters by using MHD simulations in one-dimensional flux tubes. If a gaseous planet has a magnetic field, MHD waves are excited by turbulence at the surface, dissipate in the upper atmosphere, and drive gas outflows. Our calculation shows that mass-loss rates are comparable to the observed mass-loss rates of hot Jupiters; therefore, it is suggested that gas flow driven by MHD waves can play an important role in the mass loss from gaseous planets. The mass-loss rate varies dramatically with the radius and mass of a planet: a gaseous planet with a small mass but an inflated radius produces a very large mass-loss rate. We also derive an analytical expression for the dependence of mass-loss rate on planet radius and mass that is in good agreement with the numerical calculation. The mass-loss rate also depends on the amplitude of the velocity dispersion at the surface of a planet. Thus, we expect to infer the condition of the surface and the internal structure of a gaseous planet from future observations of mass-loss rate from various exoplanets.},
doi = {10.1088/0004-637X/792/1/18},
url = {https://www.osti.gov/biblio/22365227},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 792,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}