A lithium depletion boundary age of 21 Myr for the Beta Pictoris moving group
A lithium depletion boundary age of 21 Myr for the Beta Pictoris moving group
复制标题
DOI：
10.1093/mnrasl/slt141
复制
发表时间：
2013-10
影响因子：
4.8
通讯作者：
A. Binks;R. Jeffries
中科院分区：
文献类型：
--
作者：
A. Binks;R. Jeffries
利用光谱学方法，通过径向速度、色球活动和运动学弛豫，确定了年轻β-Pic移动群（BPMG）中8个小质量候选者的成员。我们搜寻了Li I 6708 A共振特征的存在，并将结果与其他BPMG成员的文献测量结果相结合，以找到年龄相关的锂耗尽边界（LDB）-锂在同时代组中保持未燃烧的光度。BPMG的LDB年龄为2100万年± 400万年，对低质量进化模型的选择不敏感。这个年龄更精确，可能更准确，而且比BPMG通常假设的年龄要大得多。因此，BPMG成员的亚恒星和行星伴星的质量将比以前认为的更大。
Optical spectroscopy is used to confirm membership for 8 low- mass candidates in the young Beta Pic moving group (BPMG) via their radial velocities, chromospheric activity and kinematic parallaxes. We searched for the presence of the Li I 6708 ˚ A resonance feature and combined the results with literature measurements of other BPMG members to find the agedependent lithium depletion boundary (LDB) ‐ the luminosity at which Li remains unburned in a coeval group. The LDB age of the BPMG is 21 ± 4 Myr and insensitive to the choice of low-mass evolutionary models. This age is more precise, likely to be more accurate, and much older than that commonly assumed for the BPMG. As a result, substellar and planetary companions of BPMG members will be more massive than previously thought.