Periodic variability in the emission spectrum of T Tauri

¹ Shamakha Astrophysical Observatory, National Academy Sciences of Azerbaijan, Shamakha, Azerbaijan e-mail: wherbst@wesleyan.edu
² Baku State University, 23 Z. Khalilov St. 370148 Baku, Azerbaijan
³ Astronomy Department, Wesleyan University, Middletown, CT 06419, USA

Received: 23 October 2009
Accepted: 15 December 2009

Abstract

Context. Long timescale periodic variations in T Tauri stars may be related to changes in their protoplanetary disks.

Aims. A lengthy homogeneous series of spectral observations of the CTTS T TauN has been analyzed.

Methods. We search for periodicity in the equivalent widths of the emission lines in the optical and in the UV.

Results. Significant periodic variation is found in the equivalent widths of Hβ and CaII emission features on a time scale of 33 ± 1.5 days. Variations in the UV emission lines based on archival IUE spectra are also consistent with this period.

Conclusions. This is clearly not the rotation period of the star, which is known to be 2.8 days, and must arise somewhere in the magnetosphere, disk or outflow region.