Are Magnetically Active Low-Mass M Dwarfs Completely Convective?
Are Magnetically Active Low-Mass M Dwarfs Completely Convective?
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DOI：
10.1086/322336
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发表时间：
2001-09
期刊：
影响因子：
--
通讯作者：
D. J. Mullan;J. MacDonald
中科院分区：
文献类型：
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作者：
D. J. Mullan;J. MacDonald
Stars on the main sequence are expected to be completely convective if their mass lies below a certain value, Mcc. Standard stellar structure codes suggest that Mcc is in the range 0.3-0.4 M☉. In the present paper we examine several nonstandard additions to stellar structure in order to quantify their effects on the value of Mcc. We find that by including magnetic field effects, Mcc may fall to values that are significantly smaller than the standard range. This result is of interest in understanding why coronae and chromospheres in active M dwarfs fail to exhibit detectable alterations at spectral class M3-M4. The structural properties of our magnetic models also explain why active M dwarfs tend to have radii that are larger than expected for their Teff values or Teff values that are too low for their radii. Our results lead us to predict that certain stars that are classified as late L or T stars may actually have masses of 0.1-0.15 M☉.
