论文标题
蛇形星形区域中光学明亮的子群体的年龄
The Ages of Optically Bright Sub-Clusters in the Serpens Star-Forming Region
论文作者
论文摘要
Serpens分子云是500 pC内最活跃的星形形成区域之一，在不同的进化阶段，有超过一千个ysos。成员明星的年龄告知我们云的明星形成历史。在本文中，我们为附近进化的（无磁盘）年轻恒星开发了一种频谱分布（SED）拟合方法，以估计其年龄，并采用了Apogee Spectra的温度量表。与Orion选定YSO的文献温度相比，SED拟合到冷却（<5000 K）的恒星的温度平均为<〜50 K，并且对于磁盘托管和无磁极恒星的散射量为〜210 k。然后，我们将此方法应用于Serpens Molecular Cloud中的YSO，以估计先前从GAIA DR2天文学数据中鉴定出的光学成员的年龄。蛇毒中的光学成员集中在不同年龄从〜4 Myr到〜22 Myr的不同亚组中；最年轻的簇W40和Serpens South是尘土飞扬的区域，缺乏足够的光学成员，无法包括在此分析中。这些年龄证明，蛇形分子云已经形成恒星的时间比红外调查得出的时间更长。
The Serpens Molecular Cloud is one of the most active star-forming regions within 500 pc, with over one thousand of YSOs at different evolutionary stages. The ages of the member stars inform us about the star formation history of the cloud. In this paper, we develop a spectral energy distribution (SED) fitting method for nearby evolved (diskless) young stars from members of the Pleiades to estimate their ages, with a temperature scale adopted from APOGEE spectra. When compared with literature temperatures of selected YSOs in Orion, the SED fits to cool (<5000 K) stars have temperatures that differ by an average of <~ 50 K and have a scatter of ~ 210 K for both disk-hosting and diskless stars. We then apply this method to YSOs in the Serpens Molecular Cloud to estimate ages of optical members previously identified from Gaia DR2 astrometry data. The optical members in Serpens are concentrated in different subgroups with ages from ~4 Myr to ~22 Myr; the youngest clusters, W40 and Serpens South, are dusty regions that lack enough optical members to be included in this analysis. These ages establish that the Serpens Molecular Cloud has been forming stars for much longer than has been inferred from infrared surveys.
