AAS 205th Meeting, 9-13 January 2005
Session 15 Young Stellar Associations
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[15.05] The Stellar Moving Group Associated with HD 141569

A. N. Aarnio (Smith College), A. J. Weinberger (Department of Terrestrial Magnetism, Carnegie Institution of Washington)

We present results of a search for a young stellar moving group associated with the star HD 141569A, the B9.5 Ve primary member of a triple star system at 100 pc. The age of this system is only 5 ± 3 Myr as determined from placing the M-type companion stars on pre-main sequence evolutionary tracks. HD 141569A has been the subject of much investigation following imaging of its extended and morphologically complex circumstellar disk. The disk is one of the few that appears to be "transitional" between the Herbig AeBe phase and debris phase; it is optically thin yet contains measurable quantities of primordial gas. To assess the birth environment of HD 141569, for example its proximity to an OB association, and to search for other stars that might harbor transitional disks, we are interested in finding young stars that formed along with it under the same conditions.

We have searched a 30 degree region around HD 141569 for ROSAT Bright Source Catalog unresolved sources with TYCHO-2 proper motions consistent with that of HD 141569. This search yielded 48 stars, some of which are known T Tauri stars. We took visual wavelength echelle spectra of 43 of these from the Las Campanas and Lick Observatories. We find ten stars with both Li 6708Å absorption lines indicating extreme youth and radial velocities that, together with their proper motions, placed their Galactic space motions (UVW) within 1 sigma of that of HD 141569.

We discuss the space motion of this group in relation to young stars in the Scorpius-Centaurus star forming region.

This work was supported by a NASA Origins of Solar Systems grant and the NSF Research Experience for Undergraduates program.

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