On the Age of the TRAPPIST-1 System
On the Age of the TRAPPIST-1 System
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DOI：
10.3847/1538-4357/aa7fea
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发表时间：
2017-08-20
影响因子：
4.9
通讯作者：
Mamajek, Eric E.
中科院分区：
文献类型：
--
作者：
Burgasser, Adam J.;Mamajek, Eric E.
附近（d = 12 pc）的M8矮星星TRAPPIST-1（2 MASS J23062928-0502285）拥有一个紧凑的系统，至少有七颗大小与地球相似的系外行星。鉴于其重要性，测试行星的形成和演化理论，并为评估的前景，地球大小的系外行星在银河系中最常见的类型的星星轨道的可居住性，我们提出了一个全面的评估年龄的这个系统。我们整理经验的年龄限制的基础上的颜色绝对星等图，平均密度，锂吸收，表面重力特征，金属丰度，运动学，旋转和磁活动，并得出结论，TRAPPIST-1是一个过渡薄/厚盘星星的年龄为7.6 +/- 2.2 Gyr。该星星的色星等位置表明它稍微富含金属，这与之前报道的近红外光谱金属丰度一致;并且它的半径（R = 0.121 +/-0.003 R（圆点））比太阳金属丰度演化模型的预测大8%-14%。我们讨论了这个系统的稳定性和可居住性方面的老年的一些影响。
The nearby (d = 12 pc) M8 dwarf star TRAPPIST-1 (2MASS J23062928-0502285) hosts a compact system of at least seven exoplanets with sizes similar to Earth. Given its importance for testing planet formation and evolution theories, and for assessing the prospects for habitability among Earth-size exoplanets orbiting the most common type of star in the Galaxy, we present a comprehensive assessment of the age of this system. We collate empirical age constraints based on the color-absolute magnitude diagram, average density, lithium absorption, surface gravity features, metallicity, kinematics, rotation, and magnetic activity; and conclude that TRAPPIST-1 is a transitional thin/thick disk star with an age of 7.6 +/- 2.2 Gyr. The star's color-magnitude position indicates that it is slightly metal-rich, which is consistent with the previously reported near-infrared spectroscopic metallicity; and it has a radius (R = 0.121 +/- 0.003R(circle dot)) that is larger by 8%-14% than the predictions of solar-metallicity evolutionary models. We discuss some implications of the old age of this system with regard to the stability and habitability of its planets.