Photometric study on stellar magnetic activity. I. Flare variability of red dwarf stars in the open cluster M37

S. W. Chang, Yong-Ik Byun, J. D. Hartman

Research output: Contribution to journalArticle

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Abstract

Based on one-month long MMT time-series observations of the open cluster M37, we monitored light variations of nearly 2500 red dwarfs and successfully identified 420 flare events from 312 cluster M dwarf stars. For each flare light curve, we derived observational and physical parameters, such as flare shape, peak amplitude, duration, energy, and peak luminosity. We show that cool stars produce serendipitous flares energetic enough to be observed in the r-band, and their temporal and peak characteristics are almost the same as those in traditional U-band observations. We also found many large-amplitude flares with inferred in the cluster sample which had been rarely reported in previous ground-based observations. Following the ergodic hypothesis, we investigate in detail statistical properties of flare parameters over a range of energy (Er ≃ 1031-1034 erg). As expected, there are no statistical differences in the distributions of flare timescales, energies, and frequencies among stars of the same age and mass group. We note that our sample tend to have longer rise and decay timescales compared to those seen in field flare stars of the same spectral type and be more energetic. Flare frequency distributions follow power-law distributions with slopes -1.21 for all flare stars and -0.97 for stars with membership information (). These are in general agreement with previous works on flare statistics of young open clusters and nearby field stars. Our results give further support to the classical age-activity relations.

Original languageEnglish
Article number35
JournalAstrophysical Journal
Volume814
Issue number1
DOIs
Publication statusPublished - 2015 Nov 20

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red dwarf stars
open clusters
flares
energetics
timescale
energy
power law distribution
flare stars
erg
time series
dwarf stars
stars
cool stars
M stars
star distribution
frequency distribution
light curve
distribution
parameter

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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title = "Photometric study on stellar magnetic activity. I. Flare variability of red dwarf stars in the open cluster M37",
abstract = "Based on one-month long MMT time-series observations of the open cluster M37, we monitored light variations of nearly 2500 red dwarfs and successfully identified 420 flare events from 312 cluster M dwarf stars. For each flare light curve, we derived observational and physical parameters, such as flare shape, peak amplitude, duration, energy, and peak luminosity. We show that cool stars produce serendipitous flares energetic enough to be observed in the r-band, and their temporal and peak characteristics are almost the same as those in traditional U-band observations. We also found many large-amplitude flares with inferred in the cluster sample which had been rarely reported in previous ground-based observations. Following the ergodic hypothesis, we investigate in detail statistical properties of flare parameters over a range of energy (Er ≃ 1031-1034 erg). As expected, there are no statistical differences in the distributions of flare timescales, energies, and frequencies among stars of the same age and mass group. We note that our sample tend to have longer rise and decay timescales compared to those seen in field flare stars of the same spectral type and be more energetic. Flare frequency distributions follow power-law distributions with slopes -1.21 for all flare stars and -0.97 for stars with membership information (). These are in general agreement with previous works on flare statistics of young open clusters and nearby field stars. Our results give further support to the classical age-activity relations.",
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Photometric study on stellar magnetic activity. I. Flare variability of red dwarf stars in the open cluster M37. / Chang, S. W.; Byun, Yong-Ik; Hartman, J. D.

In: Astrophysical Journal, Vol. 814, No. 1, 35, 20.11.2015.

Research output: Contribution to journalArticle

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