Abstract
Low-mass stars are currently the most promising targets for detecting and characterizing habitable planets in the solar neighborhood. However, the ultraviolet (UV) radiation emitted by such stars can Erode and modify planetary atmospheres over time, drastically affecting their habitability. Thus, knowledge of the UV evolution of low-mass stars is critical for interpreting the evolutionary history of any orbiting planets. Shkolnik & Barman used photometry from the Galaxy Evolution Explorer (GALEX) to show how UV emission evolves for early-type M stars (>0.35 M o). In this paper, we extend their work to include both a larger sample of low-mass stars with known ages as well as M stars with lower masses. We find clear evidence that mid- and late-type M stars (0.08-0.35 M o) do not follow the same UV evolutionary trend as early-Ms. Lower-mass M stars retain high levels of UV activity up to field ages, with only a factor of 4 decrease on average in GALEX NUV and FUV flux density between young (<50 Myr) and old (∼5 Gyr) stars, compared to a factor of 11 and 31 for early-Ms in NUV and FUV, respectively. We also find that the FUV/NUV flux density ratio, which can affect the photochemistry of important planetary biosignatures, is mass- and age-dependent for early-Ms, but remains relatively constant for the mid- and late-type Ms in our sample.
Original language | English (US) |
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Article number | 122 |
Journal | Astronomical Journal |
Volume | 155 |
Issue number | 3 |
DOIs | |
State | Published - Mar 2018 |
Keywords
- stars: low-mass
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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HAZMAT. III. Low-mass stars GALEX photometry
Schneider, A. C. (Creator) & Shkolnik, E. (Creator), Strasbourg Astronomical Data Center, 2018
DOI: 10.26093/cds/vizier.51550122, https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/155/122
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