Photometric variability of southern T Tauri stars

Abstract

We present photometric light curves of T Tauri Stars (TTS) observed in the Southern hemisphere. Our list includes 26 TTS, half of which were discovered by the Pico dos Dias survey (PDS). The majority of the ob- served PDS stars are weak TTS and present, on average, the low range of variability typical of such stars. We mon- itored some of the stars for several seasons in order to detect possible changes in rotational modulation. In par- ticular, we nd that the classical TTS, AS 216, shows a stable period of 3.12d for three consecutive years (between 1985 and 1987) which then does not reveal itself during the observing season of 1989 and 1990. Coupled with this change during the last two observing seasons is an overall increase in the amplitude of the photometric variability in all colors. We derive photometric periods for 13 pre- viously unmonitored objects, and conrm the previously published rotational period of SY Cha. In addition, we conrm that TW Cha and SZ 82 do not reveal any signs of periodic modulation.