论文标题
Corona-Australis舞蹈。 I.使用GAIA-DR2数据重新访问恒星的普查
Corona-Australis DANCe. I. Revisiting the census of stars with Gaia-DR2 data
论文作者
论文摘要
Corona-Australis是最近和正在进行的恒星形成的最接近太阳的地区之一,但目前的恒星(和替代)内容尚未完成。我们利用Gaia太空任务的第二个数据发布来重新审视出色的人口普查,并寻找Corona-Australis年轻恒星协会的其他成员。我们应用了一种概率方法,以基于该区域乌云围绕128度$^{2} $的领域的多维星形和光度数据来推断成员资格概率。我们确定了313名高概要候选人成员的Corona-Australis协会,其中262名从未报告过成员。我们的成员样本涵盖了$ g \ gtrsim5 $ mag和$ g \ lyssim20 $ mag之间的幅度,它揭示了两个运动学上和空间上不同的子组的存在。乌云北部有一个分布式的“云云”恒星群,其两倍是历史上众所周知的“云云”种群,该人口集中在最密集的核心周围。通过将恒星在HR-DIAGRAGRAM中的位置与进化模型进行比较,我们表明这两个人群小于10 MYR。根据红外过量排放,我们在具有可用的红外光度法的来源中确定了28级II类和215级III级星,我们得出的结论是,与云的人群相比,云层区域中II级恒星(即“粘贴”恒星)的频率是两倍的大。基于此更新的人口普查为Corona-Australis区域得出的距离为$ d = 149.4^{+0.4} _ { - 0.4} $ PC,超过了先前的估计,该估计值大约为20个PC。在本文中,我们提供了Corona-Australis中最完整的星星普查,可与Gaia数据确认,可确认可确认该数据。
Corona-Australis is one of the nearest regions to the Sun with recent and ongoing star formation, but the current picture of its stellar (and substellar) content is not complete yet. We take advantage of the second data release of the Gaia space mission to revisit the stellar census and search for additional members of the young stellar association in Corona-Australis. We applied a probabilistic method to infer membership probabilities based on a multidimensional astrometric and photometric data set over a field of 128 deg$^{2}$ around the dark clouds of the region. We identify 313 high-probability candidate members to the Corona-Australis association, 262 of which had never been reported as members before. Our sample of members covers the magnitude range between $G\gtrsim5$ mag and $G\lesssim20$ mag, and it reveals the existence of two kinematically and spatially distinct subgroups. There is a distributed `off-cloud' population of stars located in the north of the dark clouds that is twice as numerous as the historically known `on-cloud' population that is concentrated around the densest cores. By comparing the location of the stars in the HR-diagram with evolutionary models, we show that these two populations are younger than 10 Myr. Based on their infrared excess emission, we identify 28 Class II and 215 Class III stars among the sources with available infrared photometry, and we conclude that the frequency of Class II stars (i.e. `disc-bearing' stars) in the on-cloud region is twice as large as compared to the off-cloud population. The distance derived for the Corona-Australis region based on this updated census is $d=149.4^{+0.4}_{-0.4}$ pc, which exceeds previous estimates by about 20 pc.In this paper we provide the most complete census of stars in Corona-Australis available to date that can be confirmed with Gaia data.