Abstract:

The Ap Sr(CrEu) star HD 75425 is shown to be pulsating with a 30- min period. This is unusually short for a Scuti star and about double the period of any known roAp star. The star is shown to be constant at the level of 0.35 mmag in the normal frequency regime of roAp pulsation (900 2500 Hz). The pulsations in HD 75425 are modulated in amplitude, but the frequencies causing this modulation cannot be identified with the data in hand. HD 75425 is a very close visual double with an insecure Ap classification which needs to be reexamined. If the Ap classification of HD 75425 is correct, and the pulsations can be linked to the peculiar star, then this Scuti-like variability is of considerable interest.

Language: English

Document Type: Regular paper

Affiliations: 1: South African Astronomical Observatory, P.O. Box 9, Observatory 7935, South Africa; E-mail: peter@saao.ac.za. 2: Department of Astronomy, University of Cape Town, Rondebosch 7700, South Africa