Four-colour photometry of eclipsing binaries^*,**

XXXIX. Light curves of the pre–main sequence triple system TY Coronae Australis

¹ Departamento de Física, ICEx, Universidade Federal de Minas Gerais, C.P. 702, 30.123–970 – Belo Horizonte, MG, Brazil
² Department of Astronomy, University of Wisconsin, Madison, Wisconsin 53706, U.S.A.
³ Niels Bohr Institute for Astronomy, Physics and Geophysics; Astronomical Observatory, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark
⁴ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A.

Send offprint request to: L.P.R. Vaz at address 1

Received: 3 July 1997
Accepted: 28 November 1997

Abstract

Complete uvby light curves of the detached Herbig Be eclipsing binary TY Coronae Australis are presented. A total of 1789 photometric measurements in each of the four colours were obtained in 1989 and in 1992-1994. A detailed analysis of the y light curve obtained in 1992-1993 is published separately (Casey et al. 1997). The reflection nebula around the system contributes about 30% of the light in all four passbands. Here we present and discuss the non-eclipse-related photometric variability of the system. We suggest that these variations are the result of variable obscuration, possibly linked to dust shells physically associated to the system.