Open AccessBrown dwarfs in the Pleiades and the initial mass function across the stellar/substellar boundary
Author(s) -
Hambly N. C.,
Hodgkin S. T.,
Cossburn M. R.,
Jameson R. F.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02283.x
Subject(s) - pleiades , physics , microdensitometer , brown dwarf , photometry (optics) , astrophysics , astronomy , observatory , stars , schmidt camera , initial mass function , stellar mass , open cluster , astrometry , star formation , optics
We present a new sample of brown dwarf (BD) candidates from a survey covering 6°× 6° centred on the Pleiades. The survey was constructed using I‐ and R‐band photographic plates, from the United Kingdom Schmidt Telescope, measured using the new high‐precision microdensitometer SuperCOSMOS at the Royal Observatory, Edinburgh. Objects as faint as or up to ∼ 0.5 mag fainter than the Pleiades lithium boundary are selected on the basis of having extremely red photographic colours and proper motions consistent with cluster membership; follow‐up near‐infrared and infrared photoelectric photometry yields nine candidate BD Pleiads. Coordinates, magnitudes and finders are presented for these objects. We use these data and information on higher mass stars to construct a mass function having an increasingly shallow gradient towards and across the stellar/substellar boundary; a few of the candidates are found at distances of more than 2° from the nominal cluster centre. We discuss the implications of these results for future surveys.