Abstract
The Ap Sr(CrEu) star HD 75425 is shown to be pulsating with a 30- min period. This is unusually short for a δ 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≤ν≤ 2500 μHz). 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 δ Scuti-like variability is of considerable interest.
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Martinez, P., Medupe, R. Discovery of 30-min oscillations in the Ap Sr(EuCr) star HD 75425. Astrophysics and Space Science 259, 57–65 (1998). https://doi.org/10.1023/A:1001567126601
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DOI: https://doi.org/10.1023/A:1001567126601