造父变星周光关系之实测研究进展  

Developments in Observational Studies on the PL Relation of Cepheids

作　　者：赵君亮[1,2] 

机构地区：[1]中国科学院上海天文台 [2]上海师范大学

出　　处：《天文学进展》2013年第3期287-306,共20页Progress In Astronomy

基　　金：国家自然科学基金(10778003)

摘　　要：造父变星周光(PL)关系对于宇宙距离尺度研究和哈勃常数测定具有重要意义,所涉及的内容颇为广泛,可包括两类不同星族造父变星的PL关系,PL关系的绝对定标,周光色(PLC)关系,PL关系的金属度效应,多波段PL关系,极大光度PL关系和多相PL关系,以及非线性形式的PL关系,等等。Cepheids have been used as very good distance indicators on Galactic and exstragalactic distance scales, based upon their period-luminosity （PL） relations. Since the Cepheids PL relation was found in 1908 by Leavitt, an American lady astronomer, lots of researches in different aspects have been done for the PL relations. Because of its great importance, it was suggested that the Cepheids PL relation should be referred to as Leavitt Law. In order to calibrate the PL relations, it is necessary to know the distances of calibrating Cepheids, which can be determined through many different approaches, such as moving cluster par- allax, statistical parallax, main sequence fitting, Baade-Wesselink method, trigonometric parallax, angular diameter measurements, etc. In recent years, some of the approaches mentioned above are combined to calibrate the PL relations. As early as 1950s, it was recognized there are two different PL relations, valid for the population I （classical） and the Population II Cepheids respectively, the zero point difference between them being some 1.5 mag. This discovery leads to the value of the Hubble constant a decrease of some 50%. In 1958, the importance of the color term was pointed out for calibration of the Cepheids PL relation, which leads to the PLC relation of Cepheids to be found. Later, some people argue that the PLC relation offers no advantage over the simpler PL relation, and others show that the PLC relation gives a much better fit to observational data than the PL relation at least in a period range. So far as the metallicity dependence of the Cepheids PL relations is concerned, a lot of discus- sions have been made. There have been different viewpoints for a long time： some people believe a single mean or ＂universal＂ PL and/or PLC relation is valid for all Cepheids in local galaxies, in- dependent of the metallicity of Cepheids under study, and others suggest that extragalactic Cepheids may not obey such a so-called universal relation. Whether the metallicity effect

关 键 词：脉动变星 造父变星 周光关系 周光色关系 金属度效应 

分 类 号：P145.2[天文地球—天体物理]