论文标题
富含锂的红色巨星的活性色球
The Active Chromospheres of Lithium-Rich Red Giant Stars
论文作者
论文摘要
我们已经收集了近300个红色巨型恒星的近红外$ ZYJ $ - 带高分辨率光谱，并具有已知的锂丰度，以调查其\ sterm {he} {i} $λ$ 10830的吸收强度。这种过渡是红巨人中色球活性和/或质量损失的指标。我们的样品中的大多数恒星基于其$ v-j，m_v $ color-magnitude图及其gaia \ teff，\ logg \ values。从通常的较低的Li丰度的意义上讲，我们的大多数目标恒星都是Li-Poor，此处定义为\ eps {li}〜$ <$ <$ 〜1.25。超过90 \％的液体恒星具有弱$λ$ 10830功能。但是，在83颗富含Li的恒星中，超过一半（\ eps {li}〜$> $ 〜1.25）具有强大的$λ$ 10830吸收。这些大的$λ$ 10830线在Li富颗恒星中表示过多的色球活性；几乎没有明显的质量损失的迹象。根据其星体数据，富含李的巨人的二元分数也可能比li-poor恒星更高。水平分支上的居住物似乎都可能在本次调查中建立的重要的Li-He连接中起作用或过去的二元相互作用。
We have gathered near-infrared $zyJ$-band high resolution spectra of nearly 300 field red giant stars with known lithium abundances in order to survey their \species{He}{i} $λ$10830 absorption strengths. This transition is an indicator of chromospheric activity and/or mass loss in red giants. The majority of stars in our sample reside in the red clump or red horizontal branch based on their $V-J,M_V$ color-magnitude diagram and their Gaia \teff, \logg\ values. Most of our target stars are Li-poor in the sense of having normally low Li abundances, defined here as \eps{Li}~$<$~1.25. Over 90\% of these Li-poor stars have weak $λ$10830 features. But more than half of the 83 Li-rich stars (\eps{Li}~$>$~1.25) have strong $λ$10830 absorptions. These large $λ$10830 lines signal excess chromospheric activity in Li-rich stars; there is almost no indication of significant mass loss. The Li-rich giants also may have a higher binary fraction than do Li-poor stars, based on their astrometric data. It appears likely that both residence on the horizontal branch and present or past binary interaction play roles in the significant Li-He connection established in this survey.
