Steve Boudreault

Max Planck Institute for Radio Astronomy

torek, 24. 2. 2009, ob 15h v F3

It is still a matter of debate whether stars and sub-stellar objects — brown dwarfs — share the same formation processes or are born differently. Since one of the scenarios for brown dwarf formation, the embryo ejection mechanism, predicts high velocity dispersion for the brown dwarfs, their radial distribution in clusters should be flatter than that of stars. Steve Boudreault uses deep photometric data of the nearby (~140pc) medium-age (50 Myr) open cluster IC 2391 to investigate this question by studying the radial variation of the mass function in the range 0.03 to 0.5 solar masses. Although he finds evidence for dynamical evolution at higher masses (> 0.15 M_sun), at the low mass end there is no evidence for a different distribution of stellar and sub-stellar objects, respectively.