LOW-MASS STARS IN THE CENTRAL REGION OF THE HYADES CLUSTER

Citation
Sk. Leggett et al., LOW-MASS STARS IN THE CENTRAL REGION OF THE HYADES CLUSTER, The Astronomical journal, 108(3), 1994, pp. 944-963
Citations number
66
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
00046256
Volume
108
Issue
3
Year of publication
1994
Pages
944 - 963
Database
ISI
SICI code
0004-6256(1994)108:3<944:LSITCR>2.0.ZU;2-F
Abstract
New V and I photometry of Hyades candidates is presented and used to i mprove the determination of the low-mass stellar population of the cen tral 5 degrees X5 degrees region of the cluster. We use color-magnitud e diagrams appropriate for the metallicity of the cluster to identify likely members from proper motion and photometric surveys, and to iden tify possible unresolved Hyades binaries. The resulting candidate samp le consists of 49 objects (38 apparently single stars plus 11 probable unresolved binaries) with 0.4 greater than or equal to, mass/M.greate r than or equal to 0.1 which have both proper motions and colors consi stent with cluster membership, plus 13 faint (19 less than or equal to V less than or equal to 22.5) objects around the hydrogen-burning lim it which lack proper motions but which have colors consistent with mem bership. We present new H alpha observations which further support the contention that Hyades members less massive than about 0.3M. all have H alpha in emission, in agreement with the expectation of longer spin down time scales for lower mass stars. A cluster luminosity function b ased on 63 individual stars is presented. Comparison with theoretical models indicates that the present cluster mass function is flat at the se low masses, implying that brown dwarfs make up no more than similar to 10% of the total mass of the cluster.