An abundance analysis of the late type supergiant Espilon Pegasi.

Spectrograms of dispersion 1.5 A/mm in the wavelength region 5600-6300 A have been used to derive the effective temperature, surface gravity, and metal abundances of the K-type supergiant, Epsilon Pegasi. The spectra were analysed with a differential curve of growth and spectrum synthesis method, based on LTE model atmospheres. Values of T5 = 4180 + 50 0K and log g = 1.0 + 0.3 are obtained, leading to a mass of approximately 10 solar masses. Relative to the solar abundances, magnesium is found to be deficient by a factor of approximately 7, silicon and titanium deficient by a factor of 2, iron peak elements deficient by a factor approximately 1.5, barium overabundant by a factor of 10, and heavy elements possibly overabundant by a factor of approximately 2. The suggestion is made that the abundances of the light elements (A < 62) in e Peg could have resulted from explosive carbon burning in the progenitor material occurring at a lower temperature than that in the solar progenitor material. Key words: abundances - nucleosynthesis - supergiants - curve of growth - spectrum synthesis