AAS 203rd Meeting, January 2004
Session 10 Young Star Clusters
Poster, Monday, January 5, 2004, 9:20am-6:30pm, Grand Hall

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[10.08] Chromospheric Activity in Young Galactic Cluster Stars

K. Soto (UC Berkeley), C. A. Pilachowski (Indiana University)

Spectra of the Ca II H and K line region of 80 late-type stars in seven young clusters were examined to obtain estimates of chromospheric activity, projected rotation velocity, radial velocity and spectral type. The spectra were obtained using the Hydra multi-fiber spectrographs on the Blanco 4-m and WIYN 3.5-m telescopes at the Cerro Tololo Interamerican Observatory and at Kitt Peak. The clusters ranged in age from the youngest, NGC 2264, at an age of about 3 million years, to the oldest, IC 4664, at an age of about 100 million years. The stars included in the study were selected to have dereddened B-V colors between 0.4 and 0.9. Chromospheric activity was estimated using indices measuring the emission in the cores of the Ca II lines compared to nearby continuum. Radial velocities were determined by cross-correlation with the solar spectrum. Projected rotation velocities were estimated by comparison with an artificially spun-up solar spectrum. No correlation was found between projected rotation speed and the degree of chromospheric activity, and stars the oldest cluster of our sample, IC 4665, showed the greatest degree of chromospheric activity.

This research was carried out through the Research Experience for Undergraduates program at Indiana University Bloomington. Support from the National Science Foundation through AST-0139617 is gratefully acknowledged.

The author(s) of this abstract have provided an email address for comments about the abstract: ktsoto@ugastro.berkeley.edu

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.