The Theta 2 Tau campaign by the Delta Scuti Network

The star Theta 2 Tau had already been studied by the Delta Scuti Network during two previous multisite campaigns (see Breger, M., Garrido, R., Huang Lin, Jiang Shi-Yang, Guo Zi-He, Frueh, M., Paparo M. Astron. Astrophys. 214, 209, 1989). The star offers a chance to study nonradial modes of different degrees and similar radial orders. The previous multisite campaigns have detected five frequencies from the photometric data. However, these data also show that there exist a number of additional, presently unidentified pulsation modes in the 10 to 15 c/d and the 25 to 30 c/d range. These new frequencies could be detected and confirmed in an additional campaign. Dziembowski and Goode (Astrophys. J.394, 670,1992) have successfully modelled the five previously identified modes, but the theoretical challenge will be provided by the frequencies of the additional modes. The star seems to differ from 4 CVn in that no variability of amplitudes could be detected so far, but the data are limited. Furthermore, during 1994 a spectroscopic MUSICOS campaign was undertaken. A new multisite photometric campaign was carried out with the Delta Scuti Network during 1994 November and December. Data has already been obtained from the McDonald, Lowell, Sierra Nevada, Xing-Long and Tien-Shan Observatories. Approximately 40 nights of photometric observations are presently being reduced.