TYC 8327-1678-1: a new super lithium-rich K giant

Abstract

In this work, we show that TYC 8327-1678-1 is a low-mass red giant star with a super lithium abundance in its atmosphere. For this, we used high-resolution spectroscopy to determine atmospheric parameters, the chemical abundances of the light elements and the isotopic ratio ¹²C/¹³C using the spectral synthesis techniques and the equivalent width measurements. Also, we used theoretical evolutionary tracks to find out the mass and the evolutionary stage of TYC 8327-1678-1. The lithium abundance was determined using the Li I resonance doublet at 6708 Å and the subordinate line at 6104 Å that yielding a mean value of $\log \, \epsilon {\rm (Li)_{NLTE}}\, =\, 3.48$ . The projected rotational velocity ( $v\, \sin \, i$ ) has been determined using spectral synthesis based on the isolated Fe I lines. Our results show that TYC 8327-1678-1 has a mass of $M\, =\, 1.60$ $\pm \, 0.20\, {\rm M}_{\odot }$ , a low rotational velocity ( $v\, \sin \, i$ = 2.35 ± 0.24 km s^-1) and metallicity of [Fe/H] = +0.23 ± 0.09. Finally, we discuss the possibility that TYC 8327-1678-1 became a lithium-rich star after a merging event involving a red giant and a helium white dwarf.