ON THE ANGULAR MOMENTUM EVOLUTION OF FULLY CONVECTIVE STARS: ROTATION PERIODS FOR FIELD M-DWARFS FROM THE MEarth TRANSIT SURVEY
ON THE ANGULAR MOMENTUM EVOLUTION OF FULLY CONVECTIVE STARS: ROTATION PERIODS FOR FIELD M-DWARFS FROM THE MEarth TRANSIT SURVEY
复制标题
关于全对流恒星的角动量演化：来自地球凌星巡天的 M 型矮星的自转周期
DOI：
10.1088/0004-637x/727/1/56
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
E. Falco
中科院分区：
文献类型：
--
作者：
J. Irwin;Z. K. Berta;C. Burke;D. Charbonneau;P. Nutzman;A. West;E. Falco
我们提出了41个场M矮星的旋转周期测量，所有这些矮星的质量都推断（从它们的视差和2微米全天巡天k波段等）在氢燃烧极限和0.35 M☉之间，因此在它们的一生中应该保持完全对流。我们测量的旋转周期范围很广，从0.28天到154天，后者与我们观测的典型灵敏度极限相称。使用运动学作为年龄的代理，我们发现大多数物体可能是厚盘或光环成员（因此，平均而言，年龄较大）旋转非常缓慢，平均周期为92天，而那些可能是薄盘成员（平均而言，年轻）的旋转周期为0.7天，尽管在厚盘样本中仍有一些快速旋转的天体。结合m矮星的文献测量结果，这些结果表明，随着恒星质量的减少，自旋下降时间增加，与先前的工作一致，并且自旋下降时间与完全对流边界以下厚盘样本的年龄相当。我们还推断，为了产生我们在厚盘候选者中观察到的缓慢旋转体，自旋下降必须在开始时消除大量的角动量，这表明完全对流的m矮星可能仍然会经历强风。
We present rotation period measurements for 41 field M-dwarfs, all of which have masses inferred (from their parallaxes and Two Micron All Sky Survey K-band magnitudes) to be between the hydrogen burning limit and 0.35 M☉ and thus should remain fully convective throughout their lifetimes. We measure a wide range of rotation periods, from 0.28 to 154 days, with the latter commensurate with the typical sensitivity limit of our observations. Using kinematics as a proxy for age, we find that the majority of objects likely to be thick disk or halo members (and hence, on average, older) rotate very slowly, with a median period of 92 days, compared with 0.7 days for those likely to be thin disk members (on average, younger), although there are still some rapid rotators in the thick disk sample. When combined with literature measurements for M-dwarfs, these results indicate an increase in spin-down times with decreasing stellar mass, in agreement with previous work, and that the spin-down time becomes comparable to the age of the thick disk sample below the fully convective boundary. We additionally infer that the spin-down must remove a substantial amount of angular momentum once it begins in order to produce the slow rotators we observe in the thick disk candidates, suggesting that fully convective M-dwarfs may still experience strong winds.