Brown Dwarfs and Mass Function of Young Open Clusters

Abstract

International audienceThe initial mass function is an important key to understand star formation processes. It is still very badly known in the substellar field and its determination is one of the principal motivations to search for brown dwarfs. I will present the results of photometric large field surveys of various clusters of similar age (Pleiades, NGC 2516 and Blanco1). The surveys of Pleiades and Blanco 1 have been carried out with the CFH-12K camera and allow to identify more than 50 candidates brown dwarfs from 0.07Msun to 0.03Msun for each cluster. NGC 2516, the twin of Pleiades in the southern hemisphere, has been observed with the ESO WFI camera and more than 100 candidate brown dwarfs have been identified in 2 square degrees. On the basis of these observations, I will present the initial mass function obtained for each cluster and I will discuss to what extent the dynamic evolution of the clusters could affect these estimates