Atmospheric parameters of PG 1605+072 and abundances of several elements have been determined at the highest accuracy achieved so far for an EC14026 pulsator. Together with the complex pulsation pattern this makes PG1605+072 the most interesting object of its class.
The high projected rotational velocity of PG 1605+072 (v sin i=39 km/s) may be a key observation to understand its puzzling power spectrum. This measurement nicely confirms a recent prediction from pulsational models (Kawaler 1999).
Although the helium abundance is low (1/30 solar) as is typical for sdB stars, most metals are only mildly depleted (0.3-0.8 dex) whereas Ne and Fe are solar. The solar iron abundance is in perfect agreement with the predictions from the diffusion models of Charpinet et al. (1997). The determination of abundances of several other elements provides a serious test of diffusion models.
© European Southern Observatory (ESO) 1999
Online publication: July 26, 1999