EDP Sciences
Free Access
Volume 380, Number 1, December II 2001
Page(s) 177 - 185
Section Formation, structure and evolution of stars
DOI https://doi.org/10.1051/0004-6361:20011340

A&A 380, 177-185 (2001)
DOI: 10.1051/0004-6361:20011340

The B-type variable HD 131120 modelled by rotational modulation

M. Briquet1, P. De Cat2, C. Aerts2 and R. Scuflaire1

1  Institut d'Astrophysique et de Géophysique de Liège, Université de Liège, avenue de Cointe 5, 4000 Liège, Belgium
2  Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Heverlee, Belgium

(Received 6 June 2001 / Accepted 17 September 2001)

We present ground-based multi-colour Geneva photometry and high-resolution spectra of the variable B-type star HD 131120. All sets of data reveal a monoperiodic star with a period of 1.569 days. We compare the variability of the star with a non-radial g-mode pulsation model and with a rotational modulation model. The latter model appears to be the best explanation for the observed line-profile variations of the star. Moreover, contrary to the pulsational model, it is able to reproduce the behaviour of the first three moments of the Si and He lines as well as the large variability of their equivalent width. We therefore remove the star from the list of new Slowly Pulsating B stars found from Hipparcos data.

Key words: stars: early-type -- stars: variables -- stars: individual: HD 131120

Offprint request: M. Briquet, briquet@astro.ulg.ac.be

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