Large-amplitude variables near the Galactic Centre
Large-amplitude variables near the Galactic Centre
复制标题
银河系中心附近的大振幅变星
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
K. Sekiguchi
中科院分区：
文献类型：
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作者：
I. Glass;S. Matsumoto;B. Carter;K. Sekiguchi
我们在这里报告了对以银河中心为中心的区域内的大振幅变星进行的4年K波段(2.2兆μm)观测的结果。总共探测到409个可能的长周期变量(LPV)，尽可能地获得它们的位置、幅度、平均幅度和周期。LPV的表面密度是Sgr I Baade窗口中的十倍以上
讨论了由星际吸收和星周吸收引起的完备性极限。大部分区域遭受了短周期LPV的星际灭绝，比长周期的LPV亮度更低，在数据中可能略有不足。极严重的物种灭绝影响到探测到变星的概率，发生在该地区不到25%的地区。
几乎所有的LPV都是Miras或OH/IR星，周期从150天到大约800天不等。在野外109个已知的OH源中，有59%的K带对应星被发现。所发现的变星的平均周期为427天，而OH/IR星的平均周期为524天。作为比较，没有已知的OH/IR星的SGR I窗口的平均周期为333d，并且只有两颗恒星被探测到，测量场中还包含一些长周期、大幅度的变星，这些变星不是OH发射体。
We report here the results of a 4-yr K-band (2.2 μm) survey for large-amplitude variable stars in a area centred on the Galactic Centre. A total of 409 likely long-period variables (LPVs) were detected, for which positions, amplitudes, average magnitudes and periods were obtained whenever possible. The surface density of LPVs is more than ten times greater than in the Sgr I Baade window at
The limits of completeness arising from interstellar and circumstellar absorption are discussed. Most of the area suffers interstellar extinction of The shorter-period LPVs are less luminous than the longer-period ones and may be slightly under-represented in the data. Extremely heavy extinction which affects the probability of detecting variables, occurs in less than 25 per cent of the area.
Almost all of the LPVs are Miras or OH/IR stars, with periods ranging from 150 d to about 800 d. K-band counterparts have been found for 59 per cent of the 109 known OH sources in the field. The average period of the variables found is 427 d, while that of the OH/IR stars is 524 d. For comparison, the average period in the Sgr I window, which contains no known OH/IR stars, is 333 d and only two stars are detected with The survey field also contains a number of long-period, large-amplitude variables that are not OH emitters.