arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.07597astro-ph.SRastro-ph.GA
收藏

M33和M31中红超巨星的周期-光度关系

The Period-Luminosity Relations of Red Supergiants in M33 and M31

Yi Ren, B. W. Jiang, Ming Yang, Jian Gao

摘要:

在M33和M31红超巨星初步样本的基础上,进一步剔除了前景星和渐近巨星分支星,得到M33红超巨星样本717个,M31红超巨星样本420个。利用近2000天的iPTF观测数据,分析了RSG的周期和振幅。根据光变曲线特征,将它们分为四类,其中M33和M31中分别有84和56个天体是半正则变星。对于这些半规则变量,通过与理论模型的比较,确定了脉动模式,在M33(M31)中产生了19(7)个第一泛音模式的源,在M33(M31)中产生了65(49)个基本模式的RSG。分析了RSG在基模下的周期-光度关系。发现在红外波段,即2 MASS $JHK_{\rm S}$波段和Spitzer短波段,P-L关系是紧密的。同时,不均匀消光导致$V$带的P-L关系散射,尘埃辐射导致Spitzer/[8.0]和[24]带的P-L关系不太紧密。在2 MASS/ $K_{\rm S}$带的P-L关系在不确定度范围内与SMC、LMC和银河系中的RSG的P-L关系一致。研究发现,在基模和第一泛音模中脉动的RSG的数目比随着金属丰度的增加而增加。

英文摘要:

Based on previously selected preliminary samples of Red Supergiants (RSGs) in M33 and M31, the foreground stars and luminous Asymptotic Giant Branch stars (AGBs) are further excluded, which leads to the samples of 717 RSGs in M33 and 420 RSGs in M31. With the time-series data from the iPTF survey spanning nearly 2000 days, the period and amplitude of RSGs are analyzed. According to the lightcurves characteristics, they are classified into four categories in which 84 and 56 objects in M33 and M31 respectively are semi-regular variables. For these semi-regular variables, the pulsation mode is identified by comparing with the theoretical model, which yielded 19 (7) sources in the first overtone mode in M33 (M31), and the other 65 (49) RSGs in M33 (M31) in the fundamental mode. The period-luminosity (P-L) relation is analyzed for the RSGs in the fundamental mode. It is found the P-L relation is tight in the infrared, i.e. the 2MASS $JHK_{\rm S}$ bands and the short-wavelength bands of Spitzer. Meanwhile, the inhomogeneous extinction causes the P-L relation scattering in the $V$ band, and the dust emission causes the less tight P-L relation in the Spitzer/[8.0] and [24] bands. The derived P-L relations in the 2MASS/$K_{\rm S}$ band are in agreement with those of RSGs in SMC, LMC and the Milky Way within the uncertainty range. It is found that the number ratio of RSGs pulsating in the fundamental mode to the first overtone mode increases with metallicity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑