The IMF and the brown dwarf population of the young cluster IC 348 derived from deep near-infrared images

Thomas Preibisch & Hans Zinnecker

Poster contribution at "The eleventh Cambridge Workshop on Cool Stars, Stellar Systems and the Sun", Tenerife, October 1999, to be published in the ASP Conference Series, in press, (1999)


We have obtained and use a deep J-band image (J_lim ~ 19) of the young cluster IC 348 to derive statistical constraints to its stellar and sub-stellar population. Our data allow us to study the luminosity function of the cluster down to ~ 3 x 10^-4 L_sun, extending well into the brown dwarf regime. We perform detailed simulations to model the observed luminosity function and find that the stellar part of the mass function is very well described by the Scalo (1998) field star IMF. We can find no evidence for the existence of a large population of brown dwarfs in IC 348. This is in a remarkable contrast to several other young clusters, which seem to harbour many brown dwarfs. We speculate that the physical environment during star formation might be the reason for this apparent difference in the quantity of the sub-stellar population of young clusters.