The first study of the light-traveltime effect in bright eclipsing binaries in the Small Magellanic Cloud

The first 100 brightest eclipsing systems from the Small Magellanic Cloud were studied for their period changes. The photometric data from the surveys OGLE-II, OGLE-III, OGLE-IV and MACHO were combined with our new CCD observations obtained using the Danish 1.54-m telescope (La Silla, Chile). Besides the period changes also the light curves were analysed using the program PHOEBE, which provided the physical parameters of both eclipsing components. For 14 of these systems the additional bodies were found, having the orbital periods from 2 to 20 yr and the eccentricities were found to be up to 0.9. Among the sample of studied 100 brightest systems we discussed the number of systems with particular period changes. About 10 per cent of these stars show eccentric orbit, about the same number have third bodies and about the same show the asymmetric light curves. © 2017 The Authors.