利用CARMENES DR1光谱研究M型矮星中可能的恒星日冕物质抛射
Investigating Possible Stellar Coronal Mass Ejections in M-type Dwarfs Using the CARMENES DR1 Spectra
浏览论文内容
中文总结 AI 辅助
本研究利用CARMENES DR1光谱分析M型矮星Hα轮廓的不对称特征，识别出61处相关特征，探讨其与恒星CME及耀斑的关联，明确相关等离子体参数及与磁场、X射线光度的关系。
中文摘要 AI 辅助
恒星日冕物质抛射（CMEs）对周围系外行星及恒星演化有显著影响。M型矮星拥有近轨道宜居带，频繁且强烈的恒星CME可能使其潜在宜居行星不适宜居住。本研究利用CARMENES DR1光谱，通过分析Hα轮廓的不对称特征，调查M型矮星中的潜在恒星CME。经全面目视检查，在33颗M型矮星的Hα线轮廓中识别出61处不同的不对称特征，这些不对称与多个色球活动线的发射增强相关，表明可能与耀斑事件存在关联。这些特征的速度均低于所研究恒星的逃逸速度，仅1例中不对称特征的最大速度接近恒星逃逸速度。尽管恒星CME是一种可能的解释，但观测到的特征也符合其他耀斑相关等离子体运动的情况。估算的运动等离子体质量范围为10^15至10^19 g，对应动能为10^29--10^32 erg。具有不对称Hα轮廓的恒星通常与更强的表面平均磁场<B>和更高的归一化X射线光度log(L_X/L_bol)相关，但我们发现线不对称率与<B>或log(L_X/L_bol)之间无显著相关性。
英文摘要
Stellar coronal mass ejections (CMEs) have significant impacts on surrounding exoplanets and stellar evolution. For M-type dwarf stars, hosting close-in habitable zones, frequent and intense stellar CMEs may render their potentially habitable planets uninhabitable. In this study, we used the CARMENES DR1 spectra to investigate potential stellar CMEs in M-type dwarfs by analyzing asymmetric features of the Hα profiles. Through a comprehensive visual inspection, we identified 61 distinct asymmetric features in the Hα line profiles across 33 M-type dwarfs. These asymmetries were associated with increased emissions in several chromospheric activity lines, indicating likely connections to flare events. The velocities of these features remain below the escape velocities of the investigated stars, except for one case where an asymmetric feature's maximum velocity approaches the star's escape velocity. While stellar CMEs are one potential explanation, the observed features are also consistent with other flare-related plasma motions. The estimated moving plasma masses range from 10^15 to 10^19 g, with corresponding kinetic energies of 10^29--10^32 erg. Stars with asymmetric Hα profiles are generally associated with stronger surface-average magnetic field <B> and higher normalized X-ray luminosity log(L_X/L_bol). However, we find no significant correlation between the line asymmetry rate and either <B> or log(L_X/L_bol).
