Kinematics and age of stellar populations in the solar neighbourhood from Hipparcos data *
V. Caloi 1,
D. Cardini 1,
F. D'Antona 2,
M. Badiali 1,
A. Emanuele 1 and
I. Mazzitelli 1
Received 23 December 1998 / Accepted 21 September 1999
The large sample of main sequence stars with Hipparcos parallaxes and estimates of the radial velocity has been used to study the relations among kinematics, age and heavy element content for the solar neighbourhood. The samples with V -30 km s-1, although including stars as old as yr, have a very young component (age yr), and have a metallicity close to the solar one. Most of the stars with space velocity component V -40 km s-1 have a minimum age of about 2 yr. Stars with V -80 km s-1 share a common age yr. The distribution in [Fe/H] of these latter objects suggests a decrease in metal content with increasing till [Fe/H] -2. For V -180 km s-1 only the metal poor component ([Fe/H] -0.7) is found. The common age for large space velocity suggests that no substantial age spread exists in the inner halo, at least in the local sample.
Key words: Galaxy: solar neighbourhood Galaxy: kinematics and dynamics Galaxy: stellar content
Send offprint requests to: V. Caloi
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This article contains no SIMBAD objects.
© European Southern Observatory (ESO) 1999
Online publication: November 16, 1999