Doppler Images and Chromospheric Variability of TWA 17

Authors :: Skelly, M. B.
Unruh, Y. C.
Barnes, J. R.
Lawson, W. A.
Donati, J. -F.
Cameron, A. Collier
Publication Year :: 2009
Abstract: We present Doppler imaging and a Balmer line analysis of the weak-line T Tauri star TWA 17. Spectra were taken in 2006 with the UCL Echelle Spectrograph on the Anglo-Australian Telescope. Using least-squares deconvolution to improve the effective signal-to-noise ratio we produced a Doppler map of the surface spot distribution. This shows similar features to maps of other rapidly rotating T Tauri stars, i.e. a polar spot with more spots extending out of it down to the equator. In addition to the photospheric variability, the chromospheric variability was studied using the Balmer emission. The mean H-alpha profile has a narrow component consistent with rotational broadening and a broad component extending out to +/-220 km/s. The variability in H-alpha suggests that the chromosphere has at least one slingshot prominence 3 stellar radii above the surface.<br />Comment: 11 pages, 15 figures, 2 tables. Accepted to MNRAS