6 Conclusions

We present high-precision photometric observations with complete uvby light curves of pre-main sequence eclipsing binary TY$\,$CrA, revealing its shallow secondary eclipse. Beyond the variations connected to the orbit (eclipses, reflection effect, etc.), the system presents non-eclipse photometric variations in time scales varying from a fraction of a day to years and which show reddening with decreasing brightness. We suggest that these variations may be linked to dust shells physically associated to the system.

Acknowledgements

This investigation was supported by allocations of ESO and Danish observing time and by grants from the Danish Natural Science Research Council, the Danish Board for Astronomical Research, and the Brazilian institutions CNPq, FAPEMIG, FINEP, CAPES. BWC acknowledges support from the Wisconsin Alumni Research Foundation and the Wisconsin Space Grant Consortium. RDM acknowledges support from a Presidential Young Investigator award and NSF grant AST94-1715. LPV gratefully acknowledges the hospitality received at the Department of Astronomy, University of Wisconsin, Madison, while being a research scholar from Aug 93 to Oct 94 (CNPq). This research has made use of the Simbad database, operated at CDS, Strasbourg, France.