Abstract

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} λ10830 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,MV color-magnitude diagram and their Gaia Teff, log(g) values. Most of our target stars are Li-poor in the sense of having normally low Li abundances. Over 90% of these Li-poor stars have weak λ10830 features. But more than half of the 83 Li-rich stars have strong λ10830 absorptions. These large λ10830 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.