skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets

Abstract

Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf, TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their surface. Temperate terrestrial planets around an M-dwarf orbit close to their parent star, rendering their atmospheres vulnerable to erosion by the stellar wind and energetic electromagnetic and particle radiation. Here, we use state-of-the-art 3D magnetohydrodynamic models to simulate the wind around TRAPPIST-1 and study the conditions at each planetary orbit. All planets experience a stellar wind pressure between 10{sup 3} and 10{sup 5} times the solar wind pressure on Earth. All orbits pass through wind pressure changes of an order of magnitude and most planets spend a large fraction of their orbital period in the sub-Alfvénic regime. For plausible planetary magnetic field strengths, all magnetospheres are greatly compressed and undergo much more dynamic change than that of the Earth. The planetary magnetic fields connect with the stellar radial field over much of the planetary surface, allowing the direct flow of stellar wind particles onto the planetary atmosphere. These conditions could result in strong atmospheric stripping and evaporation and should be taken into account for any realistic assessmentmore » of the evolution and habitability of the TRAPPIST-1 planets.« less

Authors:
; ; ; ;  [1]
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22654436
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALFVEN WAVES; DWARF STARS; EQUILIBRIUM; EROSION; EVAPORATION; EVOLUTION; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MASS; ORBITS; PARTICLES; PLANETARY ATMOSPHERES; PLANETS; PLASMA; SATELLITES; SOLAR WIND; STARS; STRIPPING; SURFACES; WATER

Citation Formats

Garraffo, Cecilia, Drake, Jeremy J., Cohen, Ofer, Alvarado-Gómez, Julian D., and Moschou, Sofia P. The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA79ED.
Garraffo, Cecilia, Drake, Jeremy J., Cohen, Ofer, Alvarado-Gómez, Julian D., & Moschou, Sofia P. The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets. United States. doi:10.3847/2041-8213/AA79ED.
Garraffo, Cecilia, Drake, Jeremy J., Cohen, Ofer, Alvarado-Gómez, Julian D., and Moschou, Sofia P. Mon . "The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets". United States. doi:10.3847/2041-8213/AA79ED.
@article{osti_22654436,
title = {The Threatening Magnetic and Plasma Environment of the TRAPPIST-1 Planets},
author = {Garraffo, Cecilia and Drake, Jeremy J. and Cohen, Ofer and Alvarado-Gómez, Julian D. and Moschou, Sofia P.},
abstractNote = {Recently, four additional Earth-mass planets were discovered orbiting the nearby ultracool M8 dwarf, TRAPPIST-1, making a remarkable total of seven planets with equilibrium temperatures compatible with the presence of liquid water on their surface. Temperate terrestrial planets around an M-dwarf orbit close to their parent star, rendering their atmospheres vulnerable to erosion by the stellar wind and energetic electromagnetic and particle radiation. Here, we use state-of-the-art 3D magnetohydrodynamic models to simulate the wind around TRAPPIST-1 and study the conditions at each planetary orbit. All planets experience a stellar wind pressure between 10{sup 3} and 10{sup 5} times the solar wind pressure on Earth. All orbits pass through wind pressure changes of an order of magnitude and most planets spend a large fraction of their orbital period in the sub-Alfvénic regime. For plausible planetary magnetic field strengths, all magnetospheres are greatly compressed and undergo much more dynamic change than that of the Earth. The planetary magnetic fields connect with the stellar radial field over much of the planetary surface, allowing the direct flow of stellar wind particles onto the planetary atmosphere. These conditions could result in strong atmospheric stripping and evaporation and should be taken into account for any realistic assessment of the evolution and habitability of the TRAPPIST-1 planets.},
doi = {10.3847/2041-8213/AA79ED},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 843,
place = {United States},
year = {2017},
month = {7}
}