PREDICTING GAIA’S PARALLAX DISTANCE TO THE CYGNUS OB2 ASSOCIATION WITH ECLIPSING BINARIES
PREDICTING GAIA’S PARALLAX DISTANCE TO THE CYGNUS OB2 ASSOCIATION WITH ECLIPSING BINARIES
复制标题
预测盖亚与天鹅座 OB2 与食双星的视差距离
DOI：
10.1088/0004-637x/811/2/85
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
M. Lundquist
中科院分区：
文献类型：
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作者：
D. Kiminki;H. Kobulnicky;C. Alvarez;M. Alexander;M. Lundquist
天鹅座OB2星群是银河系中距离我们最近、最大的大质量恒星群之一。它位于由恒星形成区域和分子云组成的“天鹅座X”复合体的中心，由于沿着这条r→80°的视线的运动距离的模糊性和严重的斑块性消失，它的距离被证明是难以捉摸的。为了完善天鹅座X关键组成部分的三维几何结构，我们测量了四个双线ob型双星的距离，它们可能是天鹅座OB2的成员。我们发现MT91 372、MT91 696、CPR2002 A36和Schulte 3的距离分别为1.33±0.17、1.32±0.07、1.44±0.18和1.32±0.13 kpc。我们采用1.33±0.06 kpc的加权平均距离。这与整个星系团的分光光度估计以及周围星际云中原恒星脉射的视差测量结果非常吻合，从而将这些云中正在进行的恒星形成与Cyg OB2联系起来。我们还确定了Schulte 3C (O9.5V)，它是4.75天二进制Schulte 3（a +B）的4″视觉伴侣，是以前未被认可的协会成员。
The Cygnus OB2 Association is one of the nearest and largest collections of massive stars in the Galaxy. Situated at the heart of the “Cygnus X” complex of star-forming regions and molecular clouds, its distance has proven elusive owing to the ambiguous nature of kinematic distances along this ℓ ≃ 80° sightline and the heavy, patchy extinction. In an effort to refine the three-dimensional geometry of key Cygnus X constituents, we have measured distances to four eclipsing double-lined OB-type spectroscopic binaries that are probable members of Cyg OB2. We find distances of 1.33 ± 0.17, 1.32 ± 0.07, 1.44 ± 0.18, and 1.32 ± 0.13 kpc toward MT91 372, MT91 696, CPR2002 A36, and Schulte 3, respectively. We adopt a weighted average distance of 1.33 ± 0.06 kpc. This agrees well with spectrophotometric estimates for the Association as a whole and with parallax measurements of protostellar masers in the surrounding interstellar clouds, thereby linking the ongoing star formation in these clouds with Cyg OB2. We also identify Schulte 3C (O9.5V), a 4″ visual companion to the 4.75 day binary Schulte 3(A+B), as a previously unrecognized Association member.