Astron. Astrophys. Suppl. Ser. 140, 293-307
A comparative study of the long-term light variations of six young irregular variables
J. Gürtler1 - C. Friedemann1
- H.-G. Reimann1 - E. Splittgerber2
- E. Rudolph3
Send offprint request: J. Gürtler
1 - Friedrich-Schiller-Universität Jena,
Astrophysikalisches Institut und Universitäts-Sternwarte,
Schillergäßchen 2, D-07745 Jena, Germany
Ludwig-Stur-Straße 5, D-06108 Halle/Saale, Germany
Lieselotte-Hermann-Straße 38a, D-07747 Jena, Germany
Received April 17, 1998; accepted September 13, 1999
We investigated the long-term light variations of six young
irregular variables, all of them UX Orionis stars or related objects.
For this aim we determined new photographic magnitudes for the five stars
VX Cas, BH Cep, BO Cep, SV Cep, and RZ Psc and made use of similar data for
WW Vul published independently. The magnitudes were
derived from Argelander brightness estimates performed on plates of the
Harvard College Observatory and Sonneberg Observatory plate collections.
The data cover a period of about 100 years and are available at the
Centre des Données Stellaires, Strasbourg.
The new data were supplemented by multicolour photoelectric
measurements taken from the literature and visual estimates collected by the
AAVSO. The resulting lightcurves are displayed and discussed. Algol-like
minima are observed with all the stars. Their properties are discussed under
the presumption that they are caused by circumstellar dust clouds orbiting
the stars. Parameters of the circumstellar dust shells are derived from
modelling the observed infrared excess radiation and compared with constraints
from the light variations.
Key words: stars: individual: VX Cas, BH Cep, BO Cep, SV Cep, RZ Psc, WW Vul --
stars: variables: general -- circumstellar matter
Copyright The European Southern Observatory (ESO)