Astron. Astrophys. Suppl. Ser. 145, 275-281

A three-year Strömgren photometric survey of suspected $\beta$ Pictoris-like stars

C. Nitschelm ¹ - A. Lecavelier des Etangs ¹ - A. Vidal-Madjar ¹ - R. Ferlet ¹ - E.H. Olsen ² - M. Dennefeld ¹

Send offprint request: C. Nitschelm

1 - Institut d'Astrophysique de Paris, CNRS, 98 bis Bld. Arago, 75014 Paris, France
2 - Niels Bohr Institue for Astronomy, Physics and Geophysics, Astronomical Observatory, Juliane Maries Vej 30, DK-2100 Copenhagen O, Denmark

Received January 4; accepted May 30, 2000

Abstract:

We carried out a Strömgren photometric survey of thirteen southern bright stars, including $\beta$ Pictoris itself, during three years, d'Astrophysique de Paris, in order to detect possible weak photometric variations. $\beta$ Pictoris presents a small long-term variation with a change of brightness by -2.1 10^-3 mag per year, over about two years from beginning of 1996, a situation relatively similar to the one about 18 years ago. Among the other stars, only HD 38392 presents weak photometric variations with a period of 21.4 days, probably related to the star rotation period. The negative result concerning photometric variations of all other stars suggests that those stars are actually really stable and strengthens the reality of the variations discovered in the case of $\beta$ Pictoris and HD 38392.

Key words: stars: $\beta$ Pic -- circumstellar matter -- planetary systems -- Strömgren photometry