Garik Israelian
The fragile and rare isotope 6Li has a spallative origin. It is rapidly destroyed in solar-type stars while fully preserved in low-mass brown dwarfs and planets. So far, 6Li has been unambigiously detected in only few metal-poor halo and disk stars whereas it has never been observed with a high level of confidence in any metal-rich or even solar metallicity star (Andersen et al. 1984, Rebolo et al. 1986). This observational fact is consistent with standard models of stellar evolution (Forestini 1984) which predict that any initial atmospheric 6Li with which the metal-rich star was born is expected to disappear within few milion years. The extended convective envelopes of young metal-rich stars are able to expose the circulating lithium to the interior temperatures exceeding 2 exp 6 K. On the other hand, some 7Li may survive the mixing process since this stable isotop is destroyed at much higher temperatures. Here we report a discovery of 6Li in the atmosphere of a metal-rich solar type star HD82943 which hosts a planetary system. The presence of the 6Li isotope in the atmosphere of HD82943 is interpreted as a direct evidence of a planet engulfed by a parent star.
Manuscript: jad8_8e.ps