TT Arietis Observed at Bucharest Observatory

Abstract

The blue peculiar variable TT Arietis (BD + 14°341), which is now thought to be an accreting (magnetic ?) white dwarf in a low-mass binary, was firstly taken as an eclipsing binary by Strohmeier et al. (1957). It was initially considered to be a nova-like variable but lately it is believed to be a possible - intermediate polar. The main argument for this classification is the difference between the photometric and spectroscopic periods of the system. Semeniuk et al. (1987) searched the quasi - periodic variability on time scale of minutes. They found a 20 min. period which appeared in the majority of nights of all observed seasons. More recently Kraicheva et al. (1987) and Roessiger (1987) have observed sudden dips in the light curve. The extraordinary character of this star requires that continous observations be made in different spectral ranges. In 1985 the Bucharest Observatory participed to an international coordinated observational campaign. TT Ari was observed on August 20/21, 21/22 and 23/24 in filters B and V, about 100 days after the return to the active state. A great amount of simultaneous optical photometric and spectroscopic data was obtained by the participating observatories. On September 27, 1992 we observed TT Ari in filter B. DM +14°0336 was used as comparison star. The observations were carried out with the 50cm Cassegrain telescope of the Bucharest Observatory. An EMI 9502B unrefrigerated photomultiplier and B filter (Schott 1mm BG 12 + Schott 1mm GG 13 ) were used. For each observed point the integration time is about 15sec.