Cepheids and other short-period variables near the Galactic Centre

作者：Matsunaga Noriyuki^*; Feast Michael W; Kawadu Takahiro; Nishiyama Shogo; Nagayama Takahiro; Nagata Tetsuya; Tamura Motohide; Bono Giuseppe; Kobayashi Naoto

来源：Monthly Notices of the Royal Astronomical Society, 2013, 429(1): 385-397.

DOI：10.1093/mnras/sts343

• binaries: eclipsing
• stars: variables: Cepheids
• Galaxy: bulge
• Galaxy: centre
• infrared: stars

We report the result of our near-infrared survey of short-period variable stars (P %26lt; 60 d) in a field of view of 20 arcmin x 30 arcmin towards the Galactic Centre (GC). Forty-five variables are discovered and we classify the variables based on their light-curve shapes and other evidence. In addition to 3 classical Cepheids reported previously, we find 16 type II Cepheids, 24 eclipsing binaries, 1 pulsating star with P = 0.265 d (RR Lyr or delta Sct) and 1 Cepheid-like variable whose nature is uncertain. Eclipsing binaries are separated into the foreground objects and those significantly obscured by interstellar extinction. One of the reddened binaries contains an O-type supergiant and its light curve indicates an eccentric orbit. We discuss the nature and distribution of type II Cepheids as well as the distance to the GC based on these Cepheids and other distance indicators. The estimates of R-0(GC) we obtained based on photometric data agree with previous results obtained with kinematics of objects around the GC. Furthermore, our result gives support to the reddening law obtained by Nishiyama and collaborators, A(Ks)/E(H - K-s) = 1.44, because a different reddening law would result in a rather different distance estimate.

• 出版日期2013-2
• 单位中国科学院国家天文台