M Dwarf Flares from Time-Resolved SDSS Spectra

Hilton, Eric J.; Hawley, Suzanne L.; West, Andrew A.; Kowalski, Adam F.

doi:10.1063/1.3099198

Cited by 4 publications

(4 citation statements)

References 46 publications

(88 reference statements)

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“…A previous study shows that the ratio increases as a function of the spectral type, from a few percent at M0 to nearly 100% at M9 [56][57][58][59]. In this work, we adopt the newer numbers from [59], which agree with later results from [60]. The numbers are read from Figure 3 of [59].…”

Section: The Radio Emission Of M Dwarf Flaressupporting

confidence: 66%

Radio Stars of the SKA

Zijlstra

Jiang

2021

Universe

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Radio emission from stars can be used, for example, to study ionized winds or stellar flares. The radio emission is faint and studies have been limited to few objects. The Square Kilometer Array (SKA) brings a survey ability to the topic of radio stars. In this paper we investigate what the SKA can detect, and what sensitivity will be required for deep surveys of the stellar Milky Way. We focus on the radio emission from OB stars, Be stars, flares from M dwarfs, and Ultra Compact HII regions. The stellar distribution in the Milky Way is simulated using the Besançon model, and various relations are used to predict their radio flux. We find that the full SKA will easily detect all UltraCompact HII regions. At the limit of 10 nJy at 5 GHz, the SKA can detect 1500 Be stars and 50 OB stars per square degree, out to several kpc. It can also detect flares from 4500 M dwarfs per square degree. At 100 nJy, the numbers become about 8 times smaller. SKA surveys of the Galactic plane should be designed for high sensitivity. Deep imaging should consider the significant number of faint flares in the field, even outside the plane of the Milky Way.

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Section: The Radio Emission Of M Dwarf Flaressupporting

confidence: 66%

Radio Stars of the SKA

Zijlstra

Jiang

2021

Universe

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“…The emission in both epochs is substantially broader and more asymmetric than expected from stellar flares, which typically show strong (Hα line-to-continuum ratios 10), narrow (FWHM < 50 km s −1 ), symmetric emission line cores (e.g., Hawley & Pettersen 1991;Hilton et al 2010). Similarly, quiescent chromospheric activity produces emission that is narrower and more symmetric than emission produced by accretion processes (White & Basri 2003).…”

Section: Brγ Spectramentioning

confidence: 85%

TIME-VARIABLE ACCRETION IN THE TW Hya STAR/DISK SYSTEM

Eisner

Doppmann

Najita

et al. 2010

ApJ

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We present two epochs of observations of TW Hya from the high-dispersion near-IR spectrograph ARIES at the MMT. We detect strong emission from the Brγ transition of hydrogen, indicating an accretion rate substantially larger than previously estimated using hydrogen line emission. The Brγ line-strength varies across our two observed epochs. We also measure circumstellar-to-stellar flux ratios (i.e., veilings) that appear close to zero in both epochs. These findings suggest that TW Hya experiences episodes of enhanced accretion while the inner disk remains largely devoid of dust. We discuss several physical mechanisms that may explain these observations.

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“…Bochanski et al 2010) and spectroscopic samples of over 40,000 M and L dwarfs . Previous SDSS studies have elucidated the mean properties of low-mass stars (Hawley et al 2002;West et al 2004West et al , 2005Bochanski et al 2007b;Schmidt et al 2010b), their magnetic activity and flaring properties as a function of mass (West et al 2004Kowalski et al 2009;Kruse et al 2010;Hilton et al 2010), as well as the structure and kinematics of the local Milky Way thin and thick disks (Bochanski et al 2007a;Jurić et al 2008;Fuchs et al 2009;Bochanski et al 2010) and the low-mass initial mass and luminosity functions (Covey et al 2008b;Bochanski et al 2010). M dwarfs have main sequence lifetimes that are considerably longer than the age of the Universe and can be used to trace the evolution of both stellar properties and the Milky Way disks.…”

Section: Introductionmentioning

confidence: 99%

The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog. I. Data

West

Morgan

Bochanski

et al. 2011

The Astronomical Journal

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283

131

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We present a spectroscopic catalog of 70,841 visually inspected M dwarfs from the seventh data release of the Sloan Digital Sky Survey. For each spectrum, we provide measurements of the spectral type, a number of molecular band heads, and the Hα, Hβ, Hγ , Hδ, and Ca ii K emission lines. In addition, we calculate the metallicity-sensitive parameter ζ and identify a relationship between ζ and the g − r and r − z colors of M dwarfs. We assess the precision of our spectral types (which were assigned by individual examination), review the bulk attributes of the sample, and examine the magnetic activity properties of M dwarfs, in particular those traced by the higher order Balmer transitions. Our catalog is cross-matched to Two Micron All Sky Survey infrared data, and contains photometric distances for each star. Finally, we identify eight new late-type M dwarfs that are possibly within 25 pc of the Sun. Future studies will use these data to thoroughly examine magnetic activity and kinematics in late-type M dwarfs and examine the chemical and dynamical history of the local Milky Way.

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M Dwarf Flares from Time-Resolved SDSS Spectra

Cited by 4 publications

References 46 publications

Radio Stars of the SKA

Radio Stars of the SKA

TIME-VARIABLE ACCRETION IN THE TW Hya STAR/DISK SYSTEM

The Sloan Digital Sky Survey Data Release 7 Spectroscopic M Dwarf Catalog. I. Data

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