High-resolution optical spectroscopy of PG 0832+676: A sharp-lined, evolved low-mass star

We present high-resolution spectroscopic observations of the faint, hot star PC 0832 + 676, identified in a previous paper as an extremely distant young B-type object. A differential abundance analysis with respect to the Galactic B-type star HR 1886 shows near normal helium, nitrogen, and oxygen abundances while there is a systematic depletion of similar to 0.4 dex in the abundances of other elements. Furthermore, our new high-resolution observations show this object to be extremely sharp lined (v sin i similar to 1 km s(-1)), and we therefore conclude that the star is an old, evolved low-mass star, either in the postasymptotic giant branch phase or more probably evolving off the blue horizontal branch. We suggest that such sharp-lined spectra from hot stars provide a unique and critical test for model atmospheric analyses, particularly with respect to the microturbulent velocity parameter.