Investigation of the Helium Enhancement in a Super Lithium Rich Giant HD
  77361
  In this work, the helium-enhancement (He-enhancement) in the lithium-rich
(Li-rich) K-giant HD 77361 is investigated using the strengths of the MgH band
and the MgI lines. The detailed abundance analysis and also the synthesis of
the MgH band and the Mg I lines has been carried out for HD 77361. One would
expect, within uncertainties, same Mg abundance from both the MgH and Mg I
lines. But, we found that Mg abundance derived from MgH lines is significantly
less than the abundance from Mg I lines, and this difference cannot be
reconciled by changing the stellar parameters within the uncertainties,
implying He enhancement in star's photosphere. The He enhancement in the
atmospheres is estimated by using models of different He/H ratios so that both
the lines, MgH as well as Mg I, return the same Mg abundance for the adopted
model's He/H ratio. We found He/H=0.4+/-0.1 as the value for HD 77361, the
normal value of He/H=0.1. Knowing the amount of He-enhancement in the Li-rich
giants is a strong clue for understanding the scenarios responsible for the Li
and He enrichment. The analysis and results are discussed.
