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arXiv 1306.2637astro-ph.SR
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一个拥有候选碎片盘的年轻的等级三元系

A young hierarchical triple system harbouring a candidate debris disc

N. R. Deacon, J. E. Schlieder, J. Olofsson, K. G. Johnston, Th. Henning

摘要:

我们报告检测到一个广泛的年轻的层次三重系统的主要有一个候选人的碎片光盘。主星TYC 5241-986-1 A是一颗已知的第谷星,我们将其归类为晚K星,其X射线、近紫外和远紫外以及Hα的发射表明它还年轻。它的自行、测光距离(65-105 pc)和径向速度使我们将该系统与广义的年轻恒星局域协联系在一起,而不是专门与任何年轻的运动群联系在一起。弱的锂吸收和X射线以及钙的H和K发射的存在支持年龄在20 ~ 1.25亿年之间。伴星是一对M4.5+-0.5的矮星,有近、远紫外线和Hα辐射,距离主星约145角秒(9200-15200天文单位)。主要有一个智慧22微米的过剩和后续赫歇尔观测也检测到一个过剩在70微米。过量的排放表明碎片盘的温度为100-175 K。我们还探讨了这种过剩可能是由于一个巧合的背景星系的可能性,并得出结论,这是不太可能的。碎片盘在年龄超过1500万年的恒星周围是非常罕见的,因此如果过量是由盘引起的,这是一个非常新颖的系统。

英文摘要:

We report the detection of a wide young hierarchical triple system where the primary has a candidate debris disc. The primary, TYC 5241-986-1 A, is a known Tycho star which we classify as a late-K star with emission in the X-ray, near and far-UV and Hα suggestive of youth. Its proper motion, photometric distance (65-105 pc) and radial velocity lead us to associate the system with the broadly defined Local Association of young stars but not specifically with any young moving group. The presence of weak lithium absorption and X-ray and calcium H and K emission support an age in the 20 to ~125 Myr range. The secondary is a pair of M4.5+-0.5 dwarfs with near and far UV and Hα emission separated by approximately 1 arcsec (~65-105 AU projected separation) which lie 145 arcsec (9200-15200 AU) from the primary. The primary has a WISE 22 micron excess and follow-up Herschel observations also detect an excess at 70 micron. The excess emissions are indicative of a 100-175 K debris disc. We also explore the possibility that this excess could be due to a coincident background galaxy and conclude that this is unlikely. Debris discs are extremely rare around stars older than 15 Myr, hence if the excess is caused by a disc this is an extremely novel system.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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