Investigating magnetic activity in very stable stellar magnetic fields: long-term photometric and spectroscopic study of the fully convective M4 dwarf V374 Peg
Investigating magnetic activity in very stable stellar magnetic fields: long-term photometric and spectroscopic study of the fully convective M4 dwarf V374 Peg
复制标题
研究非常稳定的恒星磁场中的磁活动：对全对流 M4 矮星 V374 Peg 进行长期光度和光谱研究
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
J. Kov'acs
中科院分区：
文献类型：
--
作者：
K. Vida;L. Kriskovics;K. Ol'ah;M. Leitzinger;P. Odert;Z. Kővári;H. Korhonen;Heidi J. Korhonen;R. Greimel;R. Robb;B. Cs'ak;J. Kov'acs
超快速旋转（$P_\mathrm{rot}\approx0.44 d$）完全对流的单颗M4矮星V374 Peg是研究稳定磁拓扑中强烈恒星活动的著名实验室。作为恒星磁场的可观测代理，我们研究光变曲线的稳定性，从而点配置。我们还测量了耀斑和日冕物质抛射（CME）的发生率。我们分析了光谱观测，$BV（RI）_C$测光覆盖5年，和额外的$R_C$测光，扩大了超过16年的时间基础。光变曲线显示了一个几乎是刚体旋转的天体，以及一个在大约16年内保持稳定的斑点结构，证实了之前关于一个非常稳定的磁场的迹象。我们观察到夜间时间尺度上的小变化，以及频繁的闪光，包括可能的交感闪光。最强的耀斑似乎更集中在光变曲线指示较小活动区域的相位附近。光谱数据表明，一个复杂的日冕物质抛射与回落和再喷射的材料，与最大的投影速度为$\approx$675公里/秒。我们观察到的日冕物质抛射率远低于预期的太阳耀斑日冕物质抛射与活跃恒星的关系外推。
The ultrafast-rotating ($P_\mathrm{rot}\approx0.44 d$) fully convective single M4 dwarf V374 Peg is a well-known laboratory for studying intense stellar activity in a stable magnetic topology. As an observable proxy for the stellar magnetic field, we study the stability of the light curve, and thus the spot configuration. We also measure the occurrence rate of flares and coronal mass ejections (CMEs). We analyse spectroscopic observations, $BV(RI)_C$ photometry covering 5 years, and additional $R_C$ photometry that expands the temporal base over 16 years. The light curve suggests an almost rigid-body rotation, and a spot configuration that is stable over about 16 years, confirming the previous indications of a very stable magnetic field. We observed small changes on a nightly timescale, and frequent flaring, including a possible sympathetic flare. The strongest flares seem to be more concentrated around the phase where the light curve indicates a smaller active region. Spectral data suggest a complex CME with falling-back and re-ejected material, with a maximal projected velocity of $\approx$675km/s. We observed a CME rate much lower than expected from extrapolations of the solar flare-CME relation to active stars.
解释全对流恒星中大尺度和小尺度磁场的共存
DOI：
10.1088/2041-8205/813/2/l31
发表时间：
2015
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
Christensen
通讯作者：
Christensen