arXiv 1406.76602014-06-30astro-ph.GAastro-ph.SR

银河系外盘耀斑中的造父变星

Cepheid Variables in the Flared Outer Disk of our Galaxy

Michael W. Feast, John W. Menzies, Noriyuki Matsunaga, Patricia A. Whitelock

备注：: 12 pages, 1 figure. This is almost identical to the Letter to Nature
发表信息：: Nature, 509, 342 (2014)
DOI：: 10.1038/nature13246

摘要：

银河系盘的闪耀和翘曲已经从氢原子的观测中推断出来，但是与闪耀有关的恒星迄今还没有报道。在银河系中心以外的区域，恒星大部分被尘埃遮住，气体的运动距离无法估计。最近在银河系隆起的方向上发现了32颗可能的造父变星（年轻的脉动变星）。造父变星的周期光度关系校准良好，是有用的距离指示器。当这些恒星的观测是在两种颜色，使他们的距离和红化可以同时确定，尘埃遮蔽的问题是最小的。在这里，我们报告说，五个候选人是经典造父变星。这五颗恒星分布在银河平面上方和下方约1至2千秒差距的范围内，距离中心约13至22千秒差距的径向距离。这些相对年轻（不到1.3亿年）的恒星离银道面如此之远是令人费解的，除非它们在向外张开的外盘中。如果是这样，它们可能与外分子臂有关。

英文摘要：

Flaring and warping of the disk of the Milky Way have been inferred from observations of atomic hydrogen, but stars associated with flaring have not hitherto been reported. In the area beyond the Galactic centre the stars are largely hidden from view by dust, and the kinematic distances of the gas cannot be estimated. Thirty-two possible Cepheid stars (young pulsating variable stars) in the direction of the Galactic bulge were recently identified. With their well-calibrated period-luminosity relationships, Cepheid stars are useful distance indicators. When observations of these stars are made in two colours, so that their distance and reddening can be determined simultaneously, the problems of dust obscuration are minimized. Here we report that five of the candidates are classical Cepheid stars. These five stars are distributed from approximately one to two kiloparsecs above and below the plane of the Galaxy, at radial distances of about 13 to 22 kiloparsecs from the centre. The presence of these relatively young (less than 130 million years old) stars so far from the Galactic plane is puzzling, unless they are in the flared outer disk. If so, they may be associated with the outer molecular arm.

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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英文摘要：

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