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PG 1323-086 and PG 1704+222 - two post-AGB stars at high galactic latitudes
Received 20 February 1998 / Accepted 28 April 1998
Two high galactic latitude B-type stars, PG 1323-086 and PG 1704+222 , are analysed from low and medium resolution optical spectra and Strömgren photometry. A differential abundance analysis for He, C, N, O, Mg, Al, and Si reveals that the He abundance is close to solar while metal underabundances relative to the solar value of typically 1.3 and 1.2 dex for PG 1323-086 and PG 1704+222 , respectively, are found. For both stars, carbon is even more depleted. The atmospheric parameters are consistent with evolutionary tracks for stars evolving from the asymptotic giant branch (AGB) with a stellar mass of 0.55 . The anomalous compositions are compatible with those of other high galactic latitude post-AGB stars. Hence, PG 1323-086 and PG 1704+222 are low mass post-AGB stars in an evolutionary stage between those of A- and F-type supergiants of low mass and central stars of planetary nebulae. From kinematic data and distances a population II membership is probable for both stars.
Key words: stars: abundances stars: AGB and post-AGB
Send offprint requests to: S. Moehler
Online publication: June 26, 1998