Blazhko modulation in the infrared
Blazhko modulation in the infrared
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Blazhko 红外调制
DOI：
10.1093/mnras/sty112
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发表时间：
2018
影响因子：
4.8
通讯作者：
E. Grebel
中科院分区：
文献类型：
--
作者：
J. Jurcsik;G. Hajdu;G. Hajdu;I. Dékány;J. Nuspl;M. Catelán;M. Catelán;E. Grebel
我们提出了第一个直接的证据，调制在$K $-波段的Blazhko型RR天琴座恒星，确定其长期调制的OGLE-IV的I-波段数据。本文提出了一种利用大气模式网格合成资料将K波段光变分解为温度和半径两部分的方法。对非Blazhko RRab星的温度和半径变化的计算结果与球状星团M3中RRab星的Baade-Wesselink分析结果非常一致，证明了该方法的适用性和正确性。已经发现，Blazhko调制主要由温度变化的变化驱动。半径变化起着边缘作用，而且它具有相反的符号，好像Blazhko效应是由半径变化引起的。这一结果加强了之前基于巴德-韦塞林克对M3（NGC 5272）RR天琴座的分析的发现，即半径变化的显著调制只能在径向速度测量中检测到，这依赖于在最上层大气中形成的光谱线。我们的结果给出了第一个洞察力的能量和动力学的Blazhko现象，因此它提出了强有力的限制其可能的物理解释。
We present first direct evidence of modulation in the $K$-band of Blazhko-type RR Lyrae stars that are identified by their secular modulations in the I-band data of OGLE-IV. A method has been developed to decompose the $K$-band light variation into two parts originating from the temperature and the radius changes using synthetic data of atmosphere-model grids. The amplitudes of the temperature and the radius variations derived from the method for non-Blazhko RRab stars are in very good agreement with the results of the Baade-Wesselink analysis of RRab stars in the M3 globular cluster confirming the applicability and correctness of the method. It has been found that the Blazhko modulation is primarily driven by the change in the temperature variation. The radius variation plays a marginal part, moreover it has an opposite sign as if the Blazhko effect was caused by the radii variations. This result reinforces the previous finding based on the Baade-Wesselink analysis of M3 (NGC 5272) RR Lyrae, that significant modulation of the radius variations can only be detected in radial-velocity measurements, which relies on spectral lines that form in the uppermost atmospheric layers. Our result gives the first insight into the energetics and dynamics of the Blazhko phenomenon, hence it puts strong constraints on its possible physical explanations.