The Largest M Dwarf Flares from ASAS-SN
The Largest M Dwarf Flares from ASAS-SN
复制标题
DOI：
10.3847/1538-4357/ab148d
复制
发表时间：
2018-09
期刊：
影响因子：
--
通讯作者：
S. Schmidt;B. Shappee;J. Saders;K. Stanek;Jonathan S. Brown;C. Kochanek;S. Dong;M. Drout;
中科院分区：
文献类型：
--
作者：
S. Schmidt;B. Shappee;J. Saders;K. Stanek;Jonathan S. Brown;C. Kochanek;S. Dong;M. Drout;
全天空超新星自动巡天（ASAS-SN）是现有的唯一一个大约每天用光学光扫描整个天空的项目，深度达到18倍磁。在其第一个4年的瞬态警报期间（2013-2016年），ASAS-SN观察到53个被归类为可能的M矮星耀斑的事件。我们提出了后续的测光和光谱的所有53个候选人，确认耀斑事件的47个M矮星，一个K矮星，和一个L矮星。剩下的四个天体包括一颗先前确认的金牛座T星星，一颗爆发的年轻星星，以及两颗太暗而无法确认的天体。对49个耀斑星星光变曲线的详细检查显示，5颗恒星上还有6个耀斑，导致49个天体上总共有55个耀斑，V波段对比度从ΔV =-1到-10.2不等。使用经验耀斑模型来估计耀斑光变曲线的未观测部分，我们获得了每个耀斑期间发射的V波段能量的下限，跨度为-35，这是在M矮星上探测到的能量最高的耀斑之一。ASAS-SN的M型矮耀斑星显示出更高的Hα发射比例，以及更强的Hα发射，与没有参考活动的M型矮星相比，这与属于更活跃的磁性恒星的人口相一致。我们还研究了切向速度的分布，发现ASAS-SN耀斑M矮星很可能是薄盘的成员，既不特别年轻也不特别老。
The All-sky Automated Survey for Supernovae (ASAS-SN) is the only project in existence to scan the entire sky in optical light approximately every day, reaching a depth of g ∼ 18 mag. Over the course of its first 4 yr of transient alerts (2013–2016), ASAS-SN observed 53 events classified as likely M dwarf flares. We present follow-up photometry and spectroscopy of all 53 candidates, confirming flare events on 47 M dwarfs, one K dwarf, and one L dwarf. The remaining four objects include a previously identified T Tauri star, a young star with outbursts, and two objects too faint to confirm. A detailed examination of the 49 flare star light curves revealed an additional six flares on five stars, resulting in a total of 55 flares on 49 objects ranging in V-band contrast from ΔV = −1 to −10.2 mag. Using an empirical flare model to estimate the unobserved portions of the flare light curve, we obtain lower limits on the V-band energy emitted during each flare, spanning –35, which are among the most energetic flares detected on M dwarfs. The ASAS-SN M dwarf flare stars show a higher fraction of Hα emission, as well as stronger Hα emission, compared to M dwarfs selected without reference to activity, consistent with belonging to a population of more magnetically active stars. We also examined the distribution of tangential velocities, finding that the ASAS-SN flaring M dwarfs are likely to be members of the thin disk and are neither particularly young nor old.