A comparison of OH and H2O maser properties of Mira and semiregular variable stars
A comparison of OH and H2O maser properties of Mira and semiregular variable stars
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Mira 和半规则变星 OH 和 H2O 脉泽特性的比较
DOI：
10.1046/j.1365-8711.1999.02321.x
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
A. M. Squéren
中科院分区：
文献类型：
--
作者：
M. Szymczak;A. M. Squéren
在OH和H_2O脉泽谱线上同时观测到了17颗Miras和9颗半规则变星，灵敏度分别为0.15和0.6 Jy。检测到一个新的H2O源。在Miras中，H_2O脉泽光度与OH脉泽光度有很好的相关性。由于质量损失率的增加，从半正规星到Miras，H2O与OH脉泽的亮度之比降低了大约4个数量级。一些半规则星具有典型的米拉星的脉泽特性。H2O的排放是最有可能被检测到的Miras在接近恒星速度的速度，而蓝移速度的排放占主导地位的检测从半正则。从半正则星的OH辐射通常发生在更大的红移和蓝移相对于恒星速度比OH辐射从Miras观察到。这两组恒星的平均合成脉泽剖面的差异可能与脉泽区域的速度梯度有关。这表明，一些半正则变星与脉泽发射可能是在一个较晚的恒星演化阶段比Miras。
A sample of 17 Miras and nine semiregular variable stars was simultaneously observed in the OH and H2O maser lines with sensitivities of 0.15 and 0.6 Jy, respectively. One new H2O source was detected. Among Miras the H2O maser luminosity is well correlated with the OH maser luminosity. The ratio of H2O to OH maser luminosities decreases by about four orders of magnitude from the semiregulars to the Miras as a result of an increase in the mass-loss rate. Some semiregulars have maser properties typical of Mira stars. H2O emission is most likely to be detected from Miras at velocities close to the stellar velocity, while emission at blueshifted velocities dominates the detections from semiregulars. OH emission from the semiregulars usually occurs at greater redshifts and blueshifts with respect to the stellar velocities than OH emission observed from the Miras. The differences in the average composite maser profiles in both groups of stars can be related to the velocity gradients in the maser regions. It is suggested that some semiregular variables with maser emission may be in a later stage of stellar evolution than the Miras.