CCD BVI photometry and Coravel observations of stars in the open cluster NGC2489

PIATTI, ANDRÉS E.; CLARIA OLMEDO, JUAN JOSÉ; MERMILLIOD, J.C.; PARISI, M.C.; AHUMADA, A.V.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Año: 2007 vol. 377 p. 1737 - 1746

0035-8711

We present CCD BVI photometry for the southern open cluster NGC2489 and its surrounding field. The sample consists of 2182 stars measured in an area of 13.6 × 13.6 arcmin2, extending down to V ~ 21.5. These data are supplemented with CORAVEL radial-velocity observations for seven red giant candidates. A cluster angular radius of 6.7 +/- 0.6 arcmin, equivalent to 3.5 +/- 0.3 pc, is estimated from star counts carried out inside and outside the cluster region. The comparison of the cluster colour-magnitude diagrams with isochrones of the Padova group yields E(B - V) = 0.30 +/- 0.05, E(V - I) = 0.40 +/- 0.05 and V - MV = 12.20 +/- 0.25 for log t = 8.70 (t = 500+130-100 Myr) and Z = 0.019. NGC2489 is then located at 1.8 +/- 0.3 kpc from the Sun and 25 pc below the Galactic plane. The analysis of the kinematical data allowed us to confirm cluster membership for six red giants, one of them being a spectroscopic binary. A mean radial velocity of 38.13 +/- 0.33 km s-1 was derived for the cluster red giants. The properties of a sample of open clusters aligned along the line of sight of NGC2489 are examined.