发表机构
Beijing Normal University; International Centre of Supernovae (ICESUN), Yunnan Key Laboratory; IRAP, CNRS/Université de Toulouse/CNES; SpaceSciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège; Nankai University（北京师范大学; 超新星国际中心（ICESUN），云南省重点实验室; IRAP，法国国家科学研究中心/图卢兹大学/法国国家空间研究中心; 列日大学空间科学与技术天体物理研究（STAR）研究所; 南开大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过对608颗Kepler γ Dor星的统计分析，发现组合频率多为非线性共振模式而非几何畸变产物，为星震建模提供新视角。
AI 中文摘要
寻找脉动恒星中线性组合频率的起源对于模式识别及后续的星震建模至关重要。混合型 γ Doradus (Dor) 星因其在重力 (g) 模式和压力 (p) 模式中丰富的频率内容，为此类研究提供了关键的试验平台。在此，我们对 608 颗 Kepler γ Dor 星进行了全面调查，检测到 81,265 个频率，并识别出 1,895 个谐波和 45,968 个涉及两个母频率的组合。我们的结果表明，在每颗 γ Dor 星中，线性组合的比例随频率数量的增加而增加，并在约 75% 处趋于平稳。大多数母-子振幅比分布在 100 到 10,000 之间，峰值出现在 2,000 到 4,000 之间。此外，涉及两个 g 模式母体的振幅比被发现随组合频率的增加而升高。这些值比光曲线非线性畸变所预测的值至少高一个数量级，而与非线性共振耦合的预测值则吻合良好。我们的发现表明，相当一部分组合频率可能是共振条件下的内禀模式，而非表面几何畸变的产物，这为在其他类型脉动恒星中进行系统性研究提供了新的见解。
英文摘要
The quest for the origin of linear combination frequencies in pulsating stars is critical for mode identification and subsequent seismic modeling. Hybrid γ Doradus (Dor) stars provide a crucial testbed for such investigations due to their rich frequency content in both gravity (g) and pressure (p) modes. Here, we performed a comprehensive survey of 608 Kepler γ Dor stars, detecting 81,265 frequencies, and identifying 1,895 harmonics and 45,968 combinations involving two parent frequencies. Our results suggest that the proportion of linear combinations increases with the frequency number in each γ Dor star, leveling off at approximately 75%. The majority of the parent-to-child amplitude ratios are distributed between 100 and 10,000, peaking between 2,000 and 4,000. Moreover, the amplitude ratios, involving two g-mode parents, are found to escalate with increasing combination frequency. These values are at least an order of magnitude higher than those predicted by nonlinearity distortion of the light curve, whereas they align well with those of nonlinear resonant coupling. Our findings suggest that a significant portion of combination frequencies are likely intrinsic modes under resonant conditions rather than products of surface geometric distortions, offering new insights that warrant systematic investigations across other types of pulsating star.
Comments7 pages, 8 figures, accepted for publication in A&A
