Angeli Sandoval, Allison Youngblood, R. O. Parke Loyd, Kevin France
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引用次数: 0
摘要
Ly α发射线是M和K矮星光谱中最亮的紫外发射线,是研究恒星色球、星际介质和系外行星大气的重要工具。然而,由于星际介质的强烈吸收,观测Ly α已被证明是困难的,需要从观测到的光谱中重建本征恒星线。我们对muscle国库调查的恒星进行了新的Ly α重建,包括改进的本征线翼和线核参数化。我们分析了更新的Ly α通量如何影响光化学和大气逃逸研究,以及与其他色球发射谱线(如Ca ii H和k)的通量通量缩放关系。我们发现,与以前的发现相比,我们的恒星样本的整体本征Ly α通量减少了10%,暗了约5倍。但M矮星gj581的Ly α通量增加了4%。这些结果可能对上述依赖于Ly α通量的研究影响有限。
New and Improved Lyα Reconstructions for M and K Dwarfs
The Lyα emission line is the brightest UV emission line in M and K dwarf spectra and serves as an important tool for studies of stellar chromospheres, the interstellar medium, and exoplanet atmospheres. However, Lyα observations have proven difficult due to the strong absorption by the interstellar medium, necessitating a reconstruction of the intrinsic stellar line from the observed spectrum. We have performed new Lyα reconstructions on the MUSCLES Treasury Survey stars, incorporating improved parameterizations for the intrinsic line wings and line core. We present an analysis of how the updated Lyα fluxes could impact photochemical and atmospheric escape studies and flux–flux scaling relations with other chromospheric emission lines such as Ca ii H and K. We find the overall intrinsic Lyα flux of our star sample decreases by as little as 10% to as much as ∼5× fainter compared to previous findings. The exception to this flux decrease is the M dwarf GJ 581, whose Lyα flux increased by 4%. These results will likely have a limited impact on the aforementioned studies that rely on Lyα fluxes.
期刊介绍:
The Astrophysical Journal is the foremost research journal in the world devoted to recent developments, discoveries, and theories in astronomy and astrophysics.