Detection of a Young Stellar Population in the Background of Open Clusters in the Third Galactic Quadrant

Citations Over TimeTop 10% of 2005 papers

Abstract

We report the detection of a young stellar population ($\leq$100 Myrs) in the ba ckground of 9 young open clusters belonging to a homogenoeous sample of 30 star clusters in the Third Galactic Quadrant (at $217^o \leq l \leq 260^o$). Deep and accurate UBVRI photometry allows us to measure model-independent age and distance for the clusters and the background population with high confidence. This population is exactly the same population (the Blue Plume) recently detected in 3 intermediate-age open clusters and suggested to be a $\leq$ 1-2 Gyr old population belonging to the Canis Major (CMa) over-density (Bellazzini et al. 2004, Mart\'inez-Delgado et al. 2005). However, we find that the young population in those three and in six clusters of our sample follows remarkably well the pattern of the Norma-Cygnus spiral arm as defined by CO clouds, while in the other three program clusters it lies in the Perseus arm. We finally provide one example (out of 21) of a cluster which does not show any background population, demonstrating that this population is not ubiquitous toward CMa.

Related Papers

• → Study of the nearest open clusters and the associated moving clusters by numerical simulations(2006)18 cited
• → Dynamics of Open Star Clusters(1985)38 cited
• → Dynamics of Open Star Clusters(1985)13 cited
• → The Mass Frequency-Function in Open Clusters(1957)10 cited
• → Embedded and open star clusters: basic questions(2009)1 cited