Chemical composition of evolved stars of high galactic latitude

¹ Indian Institute of Astrophysics, Bangalore 560034, India e-mail: giridhar@iiap.ernet.in
² Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 70-264, D.F. CP 04510, México e-mail: armando@astroscu.unam.mx

Received: 19 June 2004
Accepted: 11 July 2005

Abstract

We have carried out abundance analysis for a sample of high galactic latitude supergiants in search of evolved stars. We find that HD 27381 has atmospheric parameters and an abundance pattern very similar to that of the post-AGB star HD 107369. HD 10285 and HD 25291 are moderately metal-poor and show the influence of mixing that has brought the products of NeNa cycle to the surface. The high galactic latitude B supergiant HD 137569 shows selective depletion of refractory elements normally seen in post-AGB stars. We find that the high velocity B type star HD 172324 shows moderate deficiency of Fe group elements but the CNO abundances are very similar to that of disk B supergiants. The observed variations in the radial velocities, transient appearance of emission components in hydrogen line profiles and doubling of O I lines at 7774 Å  support the possibility of this star being a pulsating variable or a binary star.