SIMULTANEOUS OPTICAL AND ROSAT X-RAY OBSERVATIONS OF THE CLASSICAL T-TAURI STAR BP-TAURI

Citation
E. Gullbring et al., SIMULTANEOUS OPTICAL AND ROSAT X-RAY OBSERVATIONS OF THE CLASSICAL T-TAURI STAR BP-TAURI, Astronomy and astrophysics, 324(1), 1997, pp. 155-160
Citations number
34
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046361
Volume
324
Issue
1
Year of publication
1997
Pages
155 - 160
Database
ISI
SICI code
0004-6361(1997)324:1<155:SOARXO>2.0.ZU;2-W
Abstract
The classical T Tauri star BP Tauri has been simultaneously observed w ith UBVRI high-speed photometry at a time resolution of 2 sec and with the ROSAT PSPC detector during five nights. BP Tauri showed brightnes s variations on time scales ranging from nights to hours both in the o ptical and in the X-ray band, however, the night-to-night variations i n the optical and X-ray spectral regions were not correlated. On one o ccasion, a short term optical event with an amplitude in U of similar to 0.05(m) and a time duration of 1.2 hours occurred, with no correspo nding increase in the X-ray count rate during the decay of the event. In conclusion, the observations show that there are no detectable corr elations between the optical and X-ray variability of BP Tau on time s cales ranging from 1 hour to days. We discuss the possibility that the optical variability of BP Tau is related to accretion of circumstella r material onto the central star, while the X-ray emission presumably comes from magnetically active regions.