Galex Observations of an Energetic Ultraviolet Flare on the Dm4e Star Gj 3685a
نویسندگان
چکیده
The Galaxy Evolution Explorer (GALEX ) satellite has obtained high time resolution ultraviolet photometry during a large flare on the M4 dwarf star GJ 3685A. Simultaneous NUV (1750 2800 Å) and FUV (1350 1750 Å) time-tagged photometry with time resolution better than 0.1 s shows that the overall brightness in the FUV band increased by a factor of 1000 in 200 s. Under the assumption that the NUV emission is mostly due to a stellar continuum, and that the FUV flux is shared equally between emission lines and continuum, then there is evidence for two distinct flare components for this event. The first flare type is characterized by an exponential increase in flux with little or no increase in temperature. The other involves rapid increases in both temperature and flux. While the decay time for the first flare component may be several hours, the second flare event decayed over less than 1 minute, suggesting that there was little or no confinement of the heated plasma. Subject headings: stars: flare — stars: late-type — stars: individual (GJ 3685A) — stars: variables: other (UV Ceti) — ultraviolet: stars
منابع مشابه
GALEX high time-resolution ultraviolet observations of dMe flare events
Aims. We present near ultraviolet (NUV:1750 2800Å) and far ultraviolet (FUV: 1350 1750Å) light-curves for flares on 4 nearby dMe-type stars (GJ 3685A, CR Dra, AF Psc and SDSS J084425.9+513830.5) observed with the GALEX satellite. Methods. Taking advantage of the time-tagged events recorded with the GALEX photon counting detectors, we present high temporal resolution (< 0.01 sec) analysis of the...
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