Probing the flare atmospheres of M dwarfs using infrared emission lines

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DOIResolve DOI: http://doi.org/10.1088/0004-637X/745/1/14
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TypeArticle
Journal titleThe Astrophysical Journal
ISSN0004-637X
Volume745
Issue1
Article number14
AbstractWe present the results of a campaign to monitor active M dwarfs using infrared spectroscopy, supplemented with optical photometry and spectroscopy. We detected 16 flares during nearly 50 hr of observations on EV Lac, AD Leo, YZ CMi, and VB 8. The three most energetic flares also showed infrared emission, including the first reported detections of Pβ, Pγ, He I λ10830, and Brγ during an M dwarf flare. The strongest flare (Δu = 4.02 on EV Lac) showed emission from Hγ, Hδ, He I λ4471, and Ca II K in the UV/blue and Pβ, Pγ, Pδ, Brγ, and He I λ10830 in the infrared. The weaker flares (Δu = 1.68 on EV Lac and ΔU = 1.38 on YZ CMi) were only observed with photometry and infrared spectroscopy; both showed emission from Pβ, Pγ, and He I λ10830. The strongest infrared emission line, Pβ, occurred in the active mid-M dwarfs with a duty cycle of 3%-4%. To examine the most energetic flare, we used the static NLTE radiative transfer code RH to produce model spectra based on a suite of one-dimensional model atmospheres. Using a hotter chromosphere than previous one-dimensional atmospheric models, we obtain line ratios that match most of the observed emission lines.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Herzberg Institute of Astrophysics
Peer reviewedYes
NPARC number21270249
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Record identifier651a8ab1-3826-468a-a9f1-9c8d9912082f
Record created2014-01-16
Record modified2016-05-09
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