Astron. Astrophys. 324, 549-555 (1997)

5. Conclusions

Deep UBVRI -CCD photometry for 123 stars, down to apparent visual magnitude 21, in the central region of IC 348 open cluster was obtained. Colour-colour and colour-magnitude diagrams allow us to classify 114 of the observed stars as members of the cluster on the basis of similar colour excess and distance. For the brightest members, we give the computed individual reddening. A strong variation of the colour excess over the field is found, so large inhomogeneities in the distribution of the interstellar medium can be deduced.

The decrease in the stellar surface density towards the outer regions of the cluster as a whole, and the sub-clustering agree rather well with JHK studies by Lada & Lada (1995). A new visual sub-cluster at the south of the densest concentration (sub-cluster a) has been identified, with a surface stellar density similar to other sub-clusters in the field.

Our colour-magnitude diagrams indicate a large population of PMS stars, some of them already identified as PMS by previous authors (by their emission).

From recent PMS evolutionary models for low mass stars, we derived an age of 3-7 yr for the cluster, which is compatible with previous estimations of the age. There are indications, however, that a continous star formation model may be more reliable than a coeval model.

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998

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