CoRoT light curves of V1127 Aql

The CoRoT space mission - Convection Rotation and Planetary Transits - is a great opportunity for monitoring stars with excellent time-sampling and unprecedented photometric precision for up to 150days. As an important benefit, high-quality RR Lyrae light curves are obtained with a quasi-uninterrupted coverage over several pulsation and Blazhko cycles. The Blazhko effect in RR Lyrae stars is an unsolved problem of astrophysics. We used the high-precision space data to contribute with more precise knowledge to clear up the possible physical processes behind the phenomenon. We applied different period finding techniques including Period04, MuFrAn, PDM and SigSpec. Amplitude and phase modulation were investigated by an analytical function method as well as with the traditional O-C diagrams. The Blazhko modulation frequency is directly detected in the spectrum, as well as its first and second harmonics. It shows the non-linear nature of the Blazhko modulation. Besides the triplets, further higher-order modulation side peaks appear around the pulsation frequency as quintuplet, septuplet, nonuplet, undecaplet, tredecaplet, quindecaplet and septdecaplet structures. Additional frequencies, not belonging to the classical multiplet structures, are detected, and their linear combinations with the fundamental radial mode. We interpret these additional terms as non-radial modes. During the five consecutive Blazhko cycles, there is a shift of the maximum phase around 0.011 pulsation phase which is likely the consequence of a long term modulation.

CoRoT 太空任务——对流旋转与行星凌日观测——为监测具有卓越时间采样和前所未有的光测精度的恒星提供了绝佳机会，观测时长可达150天。作为一项重要优势，通过近乎连续的覆盖，我们获得了高质量的 RR Lyrae 星光变曲线，这些曲线覆盖了多个脉动和 Blazhko 循环。RR Lyrae 星的 Blazhko 效应是天体物理学中的一个未解之谜。我们利用高精度太空数据，以提供更精确的知识，有助于揭示该现象背后的可能物理过程。我们应用了包括 Period04、MuFrAn、PDM 和 SigSpec 在内的多种周期寻找技术。通过解析函数方法和传统的 O-C 图表，我们研究了振幅和相位的调制。Blazhko 调制频率及其一阶和二阶谐波在光谱中直接被检测到，这显示了 Blazhko 调制的非线性本质。除了三重峰之外，还观察到在脉动频率周围出现更高阶的调制旁峰，形成五重峰、七重峰、九重峰、十一重峰、十三重峰、十五重峰和十七重峰等结构。还检测到不属于经典多重峰结构之外的附加频率，这些频率与基本径向模态的线性组合。我们将这些附加项解释为非径向模式。在连续五个 Blazhko 循环期间，最大相位在 0.011 脉动相位附近发生偏移，这可能是长期调制的后果。