Periodicities in T Tauri Star Line Profiles
Session 40 -- Young Stars and T Tauri Stars
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

## [40.06] Periodicities in T Tauri Star Line Profiles

C.M. Johns and G. Basri (UC Berkeley)

Between 1986 and 1993 we have carried out repeated observations of several T Tauri stars (TTS) with the Hamilton echelle spectrometer at Lick Observatory. During several intensive campaigns, the longest occurring in Fall 1992, we obtained sufficient temporal coverage to look for periodicity in the line profiles. We have such data for 11 TTS. Here we present periodogram analyses of several of our targets, concentrating on the H$\alpha$ line profile. As of the writing of this abstract, 3 of 6 stars show evidence for periodic behavior in some portion of their line profiles. In one case (SU Aur) the detected period in the line profile variations is in good agreement with the rotation period of the star (3 days). The remaining 2 stars with detected periods in their line profile variations (DF Tau and DR Tau) do not match known photometric periods. The velocities at which the periodicities occur are quite different in each case, and correspond to different physical regions of profile formation. The stars which have not shown periodic profile variations so far are RW Aur, RY Tau, and T Tau.