Kinematics of T Tauri stars in Chamaeleon

Sabine Frink, Siegfried Röser, Juan M. Alcalá, Elvira Covino, Wolfgang Brandner, 1998, A&A 334, 873


We study the kinematics of T Tauri stars (TTS) located in the cores of the Chamaeleon clouds as well as far off these clouds. Our sample comprises 2 early type stars known to be related to Cha I , 6 classical (CTTS) and 6 weak-line T Tauri stars (WTTS) known before the ROSAT mission, and 8 bona-fide pre-main sequence (PMS) stars as well as 23 presumably older stars discovered with ROSAT (Alcalá et al. 1995; Covino et al. 1997). Altogether we present proper motions for 45 stars, taken from the Hipparcos, ACT and STARNET catalogues. For 12 stars of our sample parallaxes measured by Hipparcos are available, and we use them to derive constraints on the distance distribution of the other stars in our sample. Our analysis of the proper motions allows us to divide the sample into several subgroups.

We analyse the motions of the stars in connection with different star formation scenarios and find them consistent with both the high velocity cloud (HVC) impact model (Lépine & Duvert 1994) and the cloudlet model (Feigelson 1996), whereas the data seem to be inconsistent with any kind of a dynamical ejection model.

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