A Detailed Look at the Kinematics of the Ursa Major Stellar Kinematic Group

Session 24 - Star Formation in the Galaxy & the LMC.
Display session, Tuesday, June 10
South Main Hall,

[24.03] A Detailed Look at the Kinematics of the Ursa Major Stellar Kinematic Group

S. J. Adelman (The Citadel), D. Soderbloom (STScI), M. Mayor (Observatoire de Geneve)

In an earlier study (Soderblom amp; Mayor, 1993, AJ, 105, 226) we examined age indicators and kinematics of solar-type stars suggested as members of the Ursa Major stellar kinematic group (Eggen's Sirius Group). We determined that stars that showed spectroscopic evidence of youth appropriate to the Group's nominal age of 300 Myr also grouped together more tightly in velocity space than did the starting sample as a whole, suggesting that they really were kinematically associated with each other.

We have now used Hipparcos results to considerably refine the kinematics to look in more detail at the kinematic cohesion of this putative Group. We have extended the analysis to the earlier type stars suggested as candidate members by obtaining new ground-based radial velocity observations. The results of this analysis will be presented.

Program listing for Tuesday