Mira variables in the Galactic bulge with OGLE-II data
Mira variables in the Galactic bulge with OGLE-II data
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DOI：
10.1111/j.1365-2966.2005.09556.x
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发表时间：
2005-09
影响因子：
4.8
通讯作者：
N. Matsunaga;H. Fukushi;Y. Nakada
中科院分区：
文献类型：
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作者：
N. Matsunaga;H. Fukushi;Y. Nakada
我们从银河系凸起区的光学引力透镜实验II （OGLE-II）数据库中提取了总共1968个Mira变量。其中，1960个与2微米全天巡天（2MASS）源有关，1541个与中段空间探索（MSX）点源有关。将它们的光度特性与大麦哲伦星云和小麦哲伦星云中的Mira变星进行了比较。我们发现，具有星周物质的质量损失恒星会变红，因此吸收系数的颜色依赖性与星际物质相似。我们还讨论了凸起的结构。凸起Mira变量的表面数密度与宇宙背景探测器（COBE）卫星获得的2.2µm表面亮度有很好的相关性。利用这种关系，凸起处的Mira变量总数估计约为6 × 10 5。Mira变量的log P - K关系给出了它们的空间分布，这支持了众所周知的条形凸起的不对称性。关键词：恒星；AGB和后AGB恒星；质量损失恒星；变量；其他星系；膨胀星系；结构-红外：恒星。
We have extracted a total of 1968 Mira variables from the Optical Gravitational Lensing Experiment II (OGLE-II) data base in the Galactic bulge region. Among them, 1960 are associated with 2 Micron All-sky Survey (2MASS) sources, and 1541 are further identified with Midcourse Space Exploration (MSX) point sources. Their photometric properties are compared with those of Mira variables in the Large and Small Magellanic Clouds. We have found that mass-losing stars with circumstellar matter are reddened such that the colour dependence of the absorption coefficient is similar to that of interstellar matter. We also discuss the structure of the bulge. The surface number density of the bulge Mira variables is well correlated with the 2.2-µm surface brightness obtained by the Cosmic Background Explorer (COBE) satellite. Using this relation, the total number of Mira variables in the bulge is estimated to be about 6 × 10 5 . The log P‐K relation of the Mira variables gives their space distribution which supports the well-known asymmetry of the bar-like bulge. Ke yw ords: stars: AGB and post-AGB ‐ stars: mass-loss ‐ stars: variables: other ‐ Galaxy: bulge ‐ Galaxy: structure ‐ infrared: stars.