AI 中文总结
本研究分析3颗O型超巨星的TESS光变曲线，发现受旋转调制的g模式振荡证据，还提出旋转O型超巨星中可能存在罗斯比波，为其低频变异性提供新见解。
AI 中文摘要
O型超巨星的性质在很大程度上仍未被探索。通过分析它们的光变，我们可以揭示潜在的物理现象，如双星系统、恒星脉动和旋转模式。本研究旨在分析3颗O型超巨星的TESS光变曲线，以识别周期信号并更深入地了解它们的内部动力学和结构。我们的主要目标是寻找旋转调制的存在以及罗斯比波的潜在证据。我们进行了周期搜索，探索了相位图并搜索了旋转分裂。如果观测到的波频率与全球罗斯比波的色散关系一致，我们将其识别为该机制的潜在信号。我们使用图形方法比较观测和预测的频率。被分析的恒星HD 188001、HD 192639和HD 159952表现出一组可比较的频率。我们将其中大多数归类为g模式振荡（l=1或l=2），这与这些天体的演化状态一致。在所有案例中，我们都发现了旋转调制的证据。剩余的振荡模式可能与罗斯比模式一致，包括田型和扇型构型。我们利用文献中可用的恒星参数以及本研究中推导的旋转周期估算了旋转轴的倾角。我们还讨论了观测到的低频波与大质量超巨星测光时间序列周期图中常见的红噪声分量之间可能存在的联系。我们的结果提供了受旋转调制的g模式振荡的证据。此外，我们发现旋转的O型超巨星中可能激发罗斯比波，这表明这些大规模惯性振荡可能在这类恒星观测到的低频变异性中发挥作用。
英文摘要
The properties of O-type supergiant stars remain largely unexplored. By analysing their light variations, we can unravel underlying physical phenomena, such as binarity, stellar pulsations, and rotation modes. This study aims to analyse the TESS light curves of 3 O-type supergiants to identify periodic signatures and gain deeper insights into their internal dynamics and structure. Our primary goal is to search for the presence of rotational modulation and possible evidence of Rossby waves. A period search was performed and we explored phase diagrams and searched for rotational splitting. If the observed wave frequencies were consistent with the dispersion relation of global Rossby waves, we identified them as potential signatures of this mechanism. We used a graphical method to compare the observed and predicted frequencies. The analysed stars (HD 188001, HD 192639, and HD 159952) exhibit a comparable set of frequencies. We classify most of them as g-mode oscillations (either l=1 or l=2), in agreement with the evolutionary state of the objects. In all cases, we find evidence of rotational modulation. The remaining oscillation patterns may be consistent with Rossby modes, including both tesseral and sectoral configurations. The angle of inclination of the rotation axis was estimated using stellar parameters available in the literature, together with the rotational period derived in this work. We also discuss a possible connection between the observed low-frequency waves and the red-noise component commonly observed in the periodogram of photometric time series of massive supergiants. Our results provide evidence of g-mode oscillations modulated by rotation. In addition, we find that Rossby waves may be excited in rotating O-type supergiants, which suggests that these large-scale inertial oscillations could play a role in the observed low-frequency variability of such stars.
Comments17 pages, accepted for publication in A&A
