arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0811.1778astro-ph
收藏

色球结构的示踪I:M矮星中Ca II、K和H α的观测

Tracers of Chromospheric Structure I: Observations of Ca II K and H alpha in M Dwarfs

Lucianne M. Walkowicz, Suzanne L. Hawley

摘要:

我们报告我们的观测计划,以捕获同时光谱的钙II和巴耳末线附近的M3矮星的样本。我们的目标是调查所需的色球温度结构,以产生这些线在观测水平。我们发现一个很强的正相关性之间的瞬时测量的钙II K和巴耳末线在活跃的恒星,虽然这些线可能不是正相关的时间分辨测量。对于弱活动和中等活动的恒星,H α和Ca II K之间的关系仍然不明确,H α吸收对应于Ca II K发射的范围。Ca II K和高阶Balmer线之间也观察到类似的关系。由于我们的样品由单一的光谱类型,这些重要的色球示踪剂之间的相关性不能归因于连续效应,如其他作者所建议的。这些数据证实了先前的非同时观测的H α线的行为与增加活动,显示了初始增加的H α吸收与增加钙II K的排放,之前的H α填充,并最终成为一个纯粹的发射线在最活跃的恒星。我们还比较了我们的光学测量与档案紫外线和X射线测量,发现色球和日冕发射的高和中等活动的恒星之间的正相关性。我们比较我们的结果与以前的低质量恒星的活动部分的测定,并讨论它们在表面不均匀性的背景下。最后,我们讨论了应用这些数据作为新的静态模型的静态M矮大气的经验约束。

英文摘要:

We report on our observing program to capture simultaneous spectra of Ca II and Balmer lines in a sample of nearby M3 dwarfs. Our goal is to investigate the chromospheric temperature structure required to produce these lines at the observed levels. We find a strong positive correlation between instantaneous measurements of Ca II K and the Balmer lines in active stars, although these lines may not be positively correlated in time-resolved measurements. The relationship between H alpha and Ca II K remains ambiguous for weak and intermediate activity stars, with H alpha absorption corresponding to a range of Ca II K emission. A similar relationship is also observed between Ca II K and the higher order Balmer lines. As our sample consists of a single spectral type, correlations between these important chromospheric tracers cannot be ascribed to continuum effects, as suggested by other authors. These data confirm prior non-simultaneous observations of the H alpha line behavior with increasing activity, showing an initial increase in the H alpha absorption with increasing Ca II K emission, prior to H alpha filling in and eventually becoming a pure emission line in the most active stars. We also compare our optical measurements with archival UV and X-ray measurements, finding a positive correlation between the chromospheric and coronal emission for both high and intermediate activity stars. We compare our results with previous determinations of the active fraction of low mass stars, and discuss them in the context of surface inhomogeneity. Lastly, we discuss the application of these data as empirical constraints on new static models of quiescent M dwarf atmospheres.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑