SIMBAD references

New minima of the short period RS CVn binary system XY UMa taken in 1997-98 follow the light-time orbit with a 30.5 years period. An inferior conjunction of the third body with mass 0.23±0.03M_☉ occurred in 1979. It is suggested that the light-curves of XY UMa taken in 1978-79 were affected by the eclipse of the binary system by a dusty envelope of the protostellar object responsible also for the observed infrared excess. There is no correlation between the long-term brightness variations of the system and the minima times in the O-C diagram, so its explanation by the Applegate mechanism proposed recently by Erdem & Gueduer (1998A&AS..127..257E) is brought into question.