THE PERIOD–LUMINOSITY RELATION OF RED SUPERGIANT STARS IN THE SMALL MAGELLANIC CLOUD
THE PERIOD–LUMINOSITY RELATION OF RED SUPERGIANT STARS IN THE SMALL MAGELLANIC CLOUD
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DOI：
10.1088/0004-637x/754/1/35
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发表时间：
2012-05
期刊：
影响因子：
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通讯作者：
Ming Yang;Biwei Jiang
中科院分区：
文献类型：
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作者：
Ming Yang;Biwei Jiang
利用ASAS和CAMO计划近8-10年的观测资料，分析了小麦哲伦云（SMC）中红超巨星（RSG）的光变特征。将识别出的126个RSG分为5类：测光差的20个、无可靠周期的55个、半规则变化的6个、具有长次级周期和可分辨的短周期的15个和只有次级周期的30个。对于半正则变星和具有可分辨短周期的LSP变星，分析了KS波段的周期-光度（P-L）关系，并与银河系、大麦哲伦云和M33的P-L关系进行了比较。结果表明，除银河系外，其他星系的RSG都服从类似的P-L关系。此外，还导出了2 MASS JHKS、Spitzer/IRAC和Spitzer/MIPS 24 μm红外波段的P-L关系，具有较高的可靠性。最佳P-L关系出现在Spitzer/IRAC [3.6]和[4.5]波段。通过与P-L关系的理论计算结果的比较，提出SMC中RSG的脉动模式为一阶泛频径向模式。
The characteristics of light variation of red supergiant (RSG) stars in the Small Magellanic Cloud (SMC) are analyzed based on the nearly 8–10 year data collected by the ASAS and MACHO projects. The 126 identified RSGs are classified into five categories accordingly: 20 with poor photometry, 55 with no reliable period, 6 with semi-regular variation, 15 with a long secondary period (LSP) and distinguishable short period, and 30 with only an LSP. For the semi-regular variables and the LSP variables with distinguishable short period, the KS-band period–luminosity (P–L) relation is analyzed and compared with that of the Galaxy, the Large Magellanic Cloud, and M33. It is found that the RSGs in these galaxies obey a similar P–L relation except for those in the Galaxy. In addition, the P–L relations in the infrared bands, namely, the 2MASS JHKS, Spitzer/IRAC, and Spitzer/MIPS 24 μm bands, are derived with high reliability. The best P–L relation occurs in the Spitzer/IRAC [3.6] and [4.5] bands. Based on the comparison with the theoretical calculation of the P–L relation, the mode of pulsation of RSGs in the SMC is suggested to be the first-overtone radial mode.