HD 5980: the Wolf-Rayet binary that became a Luminous Blue Variable

BARBÁ, R.; MORRELL, N. I.; NIEMELÄ, V.; BOSCH, G.; GONZÁLEZ, J. F.; LAPPASET, E.; FERRER, O. E.; BRANDI, E.; CELLONE, S. A.; Y 6 COAUTORES

La Plata

Workshop; Colliding Winds in Binary Stars; 1995

The Wolf-Rayet eclipsing binary HD 5980 in the Small Magellanic Cloud has shown a peculiar behaviour along the past years, developing a sudden eruption during 1994, when the star changed its spectrum to one resembling those of Luminous Blue Variables. In this paper, we present the results of optical spectroscopy performed before, during and after the burst, emphasizing the evolution of different line profiles. Furthermore, the analysis of the radial velocity curves of lines from different ions suggests that the component of HD 5980. which underwent the eruptive event, is the one in front of the system during the primary eclipse.