The Rotational Evolution of Young, Binary M Dwarfs
The Rotational Evolution of Young, Binary M Dwarfs
复制标题
年轻双星 M 矮星的旋转演化
DOI：
10.3847/1538-3881/aae9ec
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
T. David
中科院分区：
文献类型：
--
作者：
J. Stauffer;L. Rebull;A. Cody;L. Hillenbrand;M. Pinsonneault;D. Barrado;J. Bouvier;T. David
我们已经分析了∼8 Myr Old上Sco协会、∼125Myr年龄昂宿星团以及∼700Myr旧毕宿星团和Praesepe开放星团中3000多颗低质量恒星的K2光曲线，以确定恒星的自转速度。其中许多K2目标显示出两个不同的周期，对于这些星团中质量最低的恒星来说，实际上所有这些有两个周期的系统都是光度双星。最有可能的解释是，我们正在探测这些双星的两个组成部分的自转周期。我们探索了光度双星相对于彼此和相对于非光度双星的自转速度的演化。在上层Sco和昂宿星团，这些低质量双星的平均周期比从M矮单恒星随机提取的周期要短得多，彼此之间的距离也更近。在上层Sco，这种差异与原始星盘造成的红外线过剩的存在或不存在密切相关--单星群体包括许多有盘的恒星，它们的自转周期平均明显长于相同质量的双星。到Praesepe年龄时，单质量M矮星和双星低质量M矮星的自转速度差异的意义要小得多，这表明全对流零龄主序星的风动量损失抹去了以后双星和单星极低质量恒星的自转速度二分法的记忆。
We have analyzed K2 light curves for more than 3000 low-mass stars in the ∼8 Myr old Upper Sco association, the ∼125 Myr age Pleiades open cluster, and the ∼700 Myr old Hyades and Praesepe open clusters to determine stellar rotation rates. Many of these K2 targets show two distinct periods, and for the lowest-mass stars in these clusters, virtually all of these systems with two periods are photometric binaries. The most likely explanation is that we are detecting the rotation periods for both components of these binaries. We explore the evolution of the rotation rate in both components of photometric binaries relative to one another and to nonphotometric binary stars. In Upper Sco and the Pleiades, these low-mass binary stars have periods that are much shorter on average and much closer to each other than would be true if drawn at random from the M dwarf single stars. In Upper Sco, this difference correlates strongly with the presence or absence of infrared excesses due to primordial circumstellar disks—the single-star population includes many stars with disks, and their rotation periods are distinctively longer on average than their binary star cousins of the same mass. By Praesepe age, the significance of the difference in rotation rate between the single and binary low-mass M dwarf stars is much less, suggesting that angular momentum loss from winds for fully convective zero-age main-sequence stars erases memory of the rotation rate dichotomy for binary and single very low mass stars at later ages.
影响因子：
6.5
作者：
T. Reinhold;A. Reiners;G. Basri
通讯作者：
T. Reinhold;A. Reiners;G. Basri