We report a discovery of the Zeeman resolved spectral lines, corresponding to the extremely large magnetic field modulus <Bs>=17.5 kG, in the cool Ap star HD 178892. The mean longitudinal field of this star reaches 7.5 kG, and its rotational modulation implies the strength of the dipolar magnetic component Bp>=23 kG. We have revised rotation period of the star using the All Sky Automated Survey photometry and determined P=8.2478 d. Rotation phases of the magnetic and photometric maxima of the star coincide with each other. We obtained Geneva photometric observation of HD 178892 and estimated Teff=7700+/-250 K using photometry and the hydrogen Balmer lines. Preliminary abundance analysis reveals abundance pattern typical of rapidly oscillating Ap stars.
@article{arxiv.astro-ph/0512319,
title = {HD 178892 - a cool Ap star with extremely strong magnetic field},
author = {T. Ryabchikova and O. Kochukhov and D. Kudryavtsev and I. Romanyuk and E. Semenko and S. Bagnulo and G. Lo Curto and P. North and M. Sachkov},
journal= {arXiv preprint arXiv:astro-ph/0512319},
year = {2009}
}
Comments
Accepted by Astronomy & Astrophysics; 4 pages, 4 figures