The embedded star clusters in the nebulae vdB-RN 92 and Gy 3–7 in Canis Majoris R1

Universidade Federal do Rio Grande do Sul, IF, CP 15051, Porto Alegre 91501–970, RS, Brazil

Corresponding author: J. B. Soares, jules@if.ufrgs.br

Received: 23 December 2002
Accepted: 25 March 2003

Abstract

We employed and photometry from the 2MASS Point Source Catalogue to study the embedded star clusters in the nebulae vdB-RN 92 and Gy 3–7, which are located in the molecular cloud Canis Majoris R1. We employed colour-colour and colour-magnitudes diagrams together with theoretical pre-main sequence isochrones to derive their fundamental parameters. Ages are based on the fraction of stars with anomalous colours, supposedly of types Herbig AeBe and T Tauri. The vdB-RN 92 cluster has an age of 5–7 Myr and the Gy 3–7 cluster ≈2 Myr. The average reddening values are A_V=4.4 and , respectively for vdB-RN 92 and Gy 3–7. The distance found for vdB-RN 92 was 1.5 kpc which is, within uncertainties, compatible with previous estimates for the complex. Gy 3–7 also appears to be related to the CMaR1 complex. We conclude that CMaR1 is a very active star-forming site, now with four star clusters in early evolutionary stages.