Planetesimals Around Stars with TESS (PAST): II. An M Dwarf “Dipper” Star with a Long-Lived Disk in the TESS Continuous Viewing Zone
Planetesimals Around Stars with TESS (PAST): II. An M Dwarf “Dipper” Star with a Long-Lived Disk in the TESS Continuous Viewing Zone
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TESS 围绕恒星运行的星子（过去）：II. 一颗 M 型矮星“北斗七星”，其盘面位于 TESS 连续观测区内
DOI：
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发表时间：
2022
影响因子：
4.8
通讯作者：
D. LaCourse
中科院分区：
文献类型：
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作者：
Gaidos Eric;A. Mann;B. Rojas;G. Feiden;M. Wood;Suchitra Narayanan;M. Ansdell;T. Jacobs;D. LaCourse
对金牛座T盘的研究为行星形成理论提供了信息;对星周尘埃掩星引起的变化的观测是对未解决的行星形成内部盘的有用探测，特别是在微弱的M矮星周围。我们报告了2 M0632的观测结果，这是一个M矮星成员的船底座年轻的移动集团，观察了TESS超过两个一年的时间间隔。组合的光变曲线包含超过300个调光事件，每个事件持续几个小时，深度达40%（0.55星等）。这些随机事件与一个独特的，稳定的1.86天周期信号相关，可能是恒星自转。同时进行的地面多波段测光显示，红化与类似ISM的尘埃一致。这颗星星在红外线的过量发射以及在光学和红外光谱中的发射线，揭示了一个类似金牛座T的吸积盘围绕着星星。我们通过对2 M0632在银河系空间运动和位置的贝叶斯分析，确认了它在船底座星系群中的成员资格。我们结合联合收割机恒星演化模型与盖亚测光和Teff的约束，光度，并在光球中没有可检测到的锂约束组和2 M0632的年龄为40-60百万年，与早期的估计一致。2 M0632加入了少数长寿磁盘的行列，挑战了磁盘寿命为1000万年的标准。所有已知的例子都围绕着M矮星，这表明这些恒星较低的X射线/紫外线照射和较慢的光蒸发可以显着影响盘的演化。由长寿盘所产生的多行星系统可能经历了显著的轨道阻尼，并迁移到近距离共振轨道，可能以TRAPPIST-1系统为代表。
Studies of T Tauri disks inform planet formation theory; observations of variability due to occultation by circumstellar dust are a useful probe of unresolved, planet-forming inner disks, especially around faint M dwarf stars. We report observations of 2M0632, an M dwarf member of the Carina young moving group that was observed by TESS over two one-year intervals. The combined light curve contains >300 dimming events, each lasting a few hours, and as deep as 40% (0.55 magnitudes). These stochastic events are correlated with a distinct, stable 1.86-day periodic signal that could be stellar rotation. Concurrent ground-based, multi-band photometry show reddening consistent with ISM-like dust. The star’s excess emission in the infrared and emission lines in optical and infrared spectra, reveal a T Tauri-like accretion disk around the star. We confirm membership of 2M0632 in the Carina group by a Bayesian analysis of its Galactic space motion and position. We combine stellar evolution models with Gaia photometry and constraints on Teff, luminosity, and the absence of detectable lithium in the photosphere to constrain the age of the group and 2M0632 to 40-60 Myr, consistent with earlier estimates. 2M0632 joins a handful of long-lived disks which challenge the canon that disk lifetimes are ≲ 10 Myr. All known examples surround M dwarfs, suggesting that lower X-ray/UV irradiation and slower photoevaporation by these stars can dramatically affect disk evolution. The multi-planet systems spawned by long-lived disks probably experienced significant orbital damping and migration into close-in, resonant orbits, and perhaps represented by the TRAPPIST-1 system.