论文标题
零元序列恒星的色圈Mg I发射线的测量
Measurements of Chromospheric Mg I Emission Lines of Zero-Age Main-Sequence Stars
论文作者
论文摘要
染色体是活跃的气氛，在这种气氛中，发生高能喷发事件（例如耀斑）。色球活性由恒星旋转和对流产生的磁场驱动。通过使用狭窄的色相球发射线（例如CA II线和MG II H和K线），对许多类型的恒星进行了广泛的检查，对许多类型的恒星的旋转周期与对流周转时间的比率（旋转周期与对流周转时间）之间的关系，旋转周期与对流周转时间的比率。但是，恒星具有较小的rossby数字，即具有快速旋转和/或长时间的对流周转时间的恒星显示了这种线条与Rossby数字的恒定强度。在这项研究中，我们使用IC 2391和IC 2602中的47个零老年序列（ZAMS）恒星的红外MG I排放线使用盎格鲁 - 澳大利亚大学伦敦大学学院伦敦大学eChelle Echelle Echelle Spectroghph的档案数据进行了研究。减去光谱吸收成分后，将MG I线被检测为45个ZAMS星星的发射线，其等效宽度在0.02 a和0.52 A之间。总共42个ZAMS恒星显示出较窄的Mg I II发射线，而不是在不同的深度形成的CA CA II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II II张。扎姆斯恒星具有较小的罗斯比数字显示出更强的Mg I发射线。即使在“ Ca II发射线的饱和度”中，MG I发射线也不饱和，即Rossby数字<10^（-1.1）。 MG I发射线被认为是色球活性的良好指标，尤其是对于活性物体。
The chromosphere is the active atmosphere in which energetic eruption events, such as flares, occur. Chromospheric activity is driven by the magnetic field generated by stellar rotation and convection. The relationship between chromospheric activity and the Rossby number, the ratio of the rotational period to the convective turnover time, has been extensively examined for many types of stars, by using narrow chromospheric emission lines, such as the Ca II lines and the Mg II h and k lines. However, the stars with small Rossby numbers, i.e., stars with rapid rotations and/or long convective turnover times, show constant strengths of such lines against the Rossby number. In this study, we investigate the infrared Mg I emission lines at 8807 A of 47 zero-age main-sequence (ZAMS) stars in IC 2391 and IC 2602 using the archive data of the Anglo-Australian Telescope at the University College London Echelle Spectrograph. After subtracting the photospheric absorption component, the Mg I line is detected as an emission line for 45 ZAMS stars, whose equivalent widths are between 0.02 A and 0.52 A. A total of 42 ZAMS stars show the narrower Mg I emission lines instead of the Ca II infrared triplet emission lines, suggesting that they are formed at different depths. The ZAMS stars with smaller Rossby numbers show stronger Mg I emission lines. The Mg I emission line is not saturated even in "the saturated regime of the Ca II emission lines," i.e., Rossby number < 10^(-1.1). The Mg I emission line is considered to be a good indicator of chromospheric activity, particularly for active objects.
