Free Access

Fig. 1


Density map in the (H, H − KS) CMD of all point-like sources in the R10 catalog with measured HKS photometry (color-filled areas), together with the 2 Myr isochrone computed by Scandariato et al. (in prep.) (solid green line, the diamond symbols correspond to 1 M and 0.1 M from top to bottom respectively). Two main populations are apparent: the ONC clustered at H  = 12 and the bona-fide background stars at H  ~  17. The latter population is to be compared with the synthetic galactic population provided by Robin et al. (2003) (solid contours) after accounting for the extinction provided by the OMC-1. The case of a constant AV = 6 across the cloud is shown in dashed contours, the highest ones roughly overlapping with the observed background population. The dotted line represents our safe selection criterion: any source fainter than H  = 15 or redder than H − KS  = 1.3 is considered a field star, provided that its colors are not compatible with the reddened Meyer’s locus (Sect. 4).

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.