Superflares and variability in solar-type stars with TESS in the Southern hemisphere
Superflares and variability in solar-type stars with TESS in the Southern hemisphere
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DOI：
10.1093/mnras/staa923
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发表时间：
2020-03
影响因子：
4.8
通讯作者：
L. Doyle;G. Ramsay;J. Doyle
中科院分区：
文献类型：
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作者：
L. Doyle;G. Ramsay;J. Doyle
太阳型恒星上的超耀斑是开普勒望远镜发射以来迅速发展的一个研究领域。多年来，有几项研究调查了这些爆炸性事件的统计数据。在这项研究中，我们提出了一个统计分析的恒星耀斑的太阳型恒星使用光度数据在2分钟的节奏从凌日系外行星调查卫星的整个南半球（部门1-13）。我们推导出旋转周期的所有恒星在我们的样本中的旋转调制存在于光变曲线作为一个结果的大星点（S）的表面上。我们从209颗太阳型恒星中识别出1980个能量在1031-1036 erg（使用太阳耀斑分类，这对应于X1-X100 000）的恒星耀斑，并对其性质进行了分析。我们调查的旋转阶段的耀斑，并没有发现任何阶段的偏好，这表明耀斑是随机分布的。作为基准，我们使用太阳耀斑的GOES数据详细的太阳耀斑和太阳黑子之间的密切关系。此外，我们还计算了每个恒星的近似光斑面积，并将其与耀斑数量，旋转相位和耀斑能量进行比较。此外，我们的两颗恒星被观察到在连续观察区的光变曲线跨越1年，因此，我们更详细地研究这些恒星的恒星变化。
Superflares on solar-type stars have been a rapidly developing field ever since the launch of Kepler. Over the years, there have been several studies investigating the statistics of these explosive events. In this study, we present a statistical analysis of stellar flares on solar-type stars made using photometric data in 2-min cadence from Transiting Exoplanet Survey Satellite of the whole Southern hemisphere (sectors 1–13). We derive rotational periods for all the stars in our sample from rotational modulations present in the light curve as a result of large star-spot(s) on the surface. We identify 1980 stellar flares from 209 solar-type stars with energies in the range of 1031–1036 erg (using the solar flare classification, this corresponds to X1–X100 000) and conduct an analysis into their properties. We investigate the rotational phase of the flares and find no preference for any phase, suggesting the flares are randomly distributed. As a benchmark, we use GOES data of solar flares to detail the close relationship between solar flares and sunspots. In addition, we also calculate approximate spot areas for each of our stars and compare this to flare number, rotational phase, and flare energy. Additionally, two of our stars were observed in the continuous viewing zone with light-curves spanning 1 yr; as a result we examine the stellar variability of these stars in more detail.