Coronal Mass Ejection (CME) Activity of Low Mass M Stars as An Important Factor for The Habitability of Terrestrial Exoplanets. I. CME Impact on Expected Magnetospheres of Earth-Like Exoplanets in Close-In Habitable Zones

• DOI: 10.1089/ast.2006.0127
• Publication Date: 2007-04-03T20:08:15Z
• Authors: Maxim L. Khodachenko; Ignasi Ribas; Helmut Lammer; Jean-Mathias Grie...; Martin Leitner; Franck Selsis; Carlos Eiroa; Arnold Hanslmeier; Helfried K. Biernat; Charles J. Farrugia; Helmut O. Rucker
• Keywords: Planetary habitability

Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for target star lists terrestrial exoplanet (i.e., planets with mass, radius, internal parameters identical to Earth) search programs like Darwin (ESA) or Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level stellar activity low M stars, compared G well closer orbital distances their habitable zones (HZs), means that terrestrial-type exoplanets within HZs these influenced by one would expect a planet an HZ star. Here we examine influences coronal ejection (CME) on planetary environments role CMEs play definition habitability criterion type near We pay attention fact close proximity become tidally locked, which, turn, can result relatively weak intrinsic magnetic moments. Taking into account existing observational data models involve Sun related hypothetical extrasolar (density, velocity, size, occurrence rate), show Earth-like close-in should experience continuous CME exposure over long periods time. This fact, together small moments locked exoplanets, little no magnetospheric protection atmospheres from dense flow plasma. Magnetospheric standoff weakly magnetized at ≤0.1 AU be shrunk, under action CMEs, altitudes about 1,000 km above surface. Such compressed magnetospheres have crucial consequences atmospheric erosion processes. Key Words: stars—Stellar activity—Coronal ejections—Habitability—Terrestrial exoplanets—Planetary magnetospheres—Terrestrial finding missions. Astrobiology 7(1), 167–184.