Astron. Astrophys. Suppl. Ser. 133, 25-28

CCD photometry of distant open clusters

IV. Trumpler 5

J. Kaluzny

Send offprint request: J. Kaluzny

Warsaw University Observatory, Al. Ujazdowskie  4, 00-478 Warsaw, Poland
e-mail: jka@sirius.astrouw.edu.pl

Received April 21; accepted May 13, 1998

Abstract:

We present BVI photometry for Trumpler 5, a rich open cluster located in the Galactic anticenter. The cluster age is slightly lower than the age of M 67. Its distance modulus (m-M)₀ and reddening E(B-V) are estimated at 12.4 and 0.58, respectively. These values were obtained for the assumed solar metallicity of the cluster. Our data indicate that Tr 5 is one of the richest objects among the sample of known old open clusters. The total mass included only in upper-main sequence stars exceeds 3000 $m_{\odot}$. The angular diameter of the cluster is estimated at 11.6 arcmin, which corresponds to a linear size of about 20 pc for an estimated distance $d\approx 3.0$ kpc.

Key words: open clusters and associations: individual: Trumpler 5 -- HR diagram