~6li In The Atmosphere Of Gj 117 Revisited

摘要

Detection of ~6 Li has been shown for energetic solar events, one chromospherically active binary, and several dwarf halo stars. We had previously found a ~6Li/~7Li = 0.03 ± 0.01 for active K dwarf GJ 117 using VLT UVES observations. Here we present high signal-to-noise (> 1000) high spectral resolution observations taken with the McDonald Observatory's 2.7 m and echelle spectrometer of GJ 117. We have used the solar spectrum and template stars to eliminate possible blends, such as Ti I, in the ~6Li spectral region. Our new analysis, using an updated PHOENIX model atmosphere, finds ~6Li/~7Li = 0.05 ± 0.02. In addition, bisector analysis showed no significant red asymmetries that would affect the lithium line profile. No changes above the statistical uncertainties are found between the VLT and McDonald data. The amount of ~6Li derived for GJ 117 is consistent with creation in spallation reactions on the stellar surface, but we caution that uncertainties in the continuum level may cause additional uncertainty in the ~6Li fraction.