论文标题
RRAB变量在不同的脉动期间具有相同的光曲线形状
RRab variables with identical light-curve shapes at different pulsation periods
论文作者
论文摘要
在本文中，我们报告了使用OGLE-IV调查的银河系凸起数据的检测带有准形状光曲线的RRAB恒星，但周期差异为$ 0.05-0.21 $ d。我们已经检查了比Oosterhoff距离的恒星短。这些恒星通常具有较小的振幅和较大的傅立叶相分化，比典型的凸起rrab恒星在同一时期具有。这些“异常”恒星中的许多具有优质的光曲线，没有任何Blazhko调制的迹象。检查它们的傅立叶参数表明，其中几个恒星与典型的凸起RR Lyrae非常相似。我们在“异常”和基于Ogle $ i $ band数据的“异常”和“正常”位置rrab星之间发现了数百个准形状的光曲线对。还检查了这些星星的$ v $ -band，以及这些恒星的$ k_s $ - ，$ k_s $ - ，$ k_s $ - ，$ k_s $ - ，以及这些恒星的$ r $ band数据的数据，还检查了光曲线形状的相似性。最后，确定了每个可用光度带中具有相同形状光曲线的149对。使用经验公式计算变量的物理属性，平均$ -0.5 $ 〜DEX，$ -0.13 $ 〜MAG，0.67和165〜K [Fe/H]，$ M_V $，$ R/R/R_ \ odot $，$ r_v $，odot $和$ t _ {与长期变量相比，恒星较少的金属贫困，淡淡，更小，更热。解释具有不同物理特性和脉动周期的变量的存在，但形状相同的光曲线是建模的挑战性任务。
In this paper, we report on the detection of RRab stars with quasi-identical-shape light curves but period differences as large as $0.05-0.21$ d using the Galactic bulge data of the OGLE-IV survey. We have examined stars with shorter periods than the Oosterhoff~I ridge of the bulge. These stars generally have smaller amplitudes and larger Fourier phase-differences than the typical bulge RRab stars have at the same period. Many of these "anomalous" stars have good-quality light curves without any sign of the Blazhko modulation. Examining their Fourier parameters revealed that several of these stars show very similar light-curve to the typical bulge RR Lyrae. We found hundreds of quasi-identical-shape light-curve pairs with different periods between the "anomalous"- and the "normal"-position RRab stars based on the OGLE $I$-band data. The OGLE $V$-band, and the archive VVV and MACHO surveys $K_s$-, $b$- and $r$-band data of these stars were also checked for light-curve-shape similarity. Finally, 149 pairs with identical-shape light curves in each available photometric band were identified. Calculating the physical properties of the variables using empirical formulae, on average, $-0.5$~dex, $-0.13$~mag, 0.67, and 165~K differences between the [Fe/H], $M_V$, $R/R_\odot$, and $T_{\mathrm{eff}}$ values of the members of the pairs are derived, being the short-period stars less metal-poor, fainter, smaller and hotter than the long-period variables. To explain the existence of variables with different physical properties and pulsation periods but with identical-shape light curves is a challenging task for modelling.
