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Accueil > Séminaires > Archive des séminaires d’Utinam > Archive des séminaires d’astrophysique (jusqu’en 2011) > 2011

Young Brown Dwarfs Search in the Core of Distant Massive Star Forming Regions

par Edith Burgey -

Le jeudi 20 octobre à 14h., Salle de conférences de l’Observatoire

Par Devendra Ojha, Tata Institute of Fundamental Research (TIFR), Mumbai, India

Abstract :

So far young brown dwarfs (YBDs) search has been limited to the nearby
star forming regions (< 500 pc). With the high sensitivity and high
resolution NIR observations, it is now possible to detect and characterize
the YBDs in distant massive star forming regions, which are more typical
in the galactic scale. W3 Main and NGC 7538 are well-known distant massive
star forming regions and contain rich clusters of young stars which
have recently been formed. Several different evolutionary stages have been
discovered in these complexes with considerable substructures and it is
expected that the stellar population in these star forming regions is
primarily composed of low mass pre-main-sequence stars. In this talk, I
will describe results from our ongoing investigation of low-mass stellar
and substellar populations in W3 Main and NGC 7538, using the deep NIR
observations (K 20 mag at 10-sigma) with the Subaru Telescope. There
appears to be a substantial substellar population and we expect to reveal
the IMFs down to 30 Jupiter mass regime in the W3 Main and NGC 7538
regions, by detecting YBDs based on the NIR colors and luminosities. It
is unlikely that the mass functions show the presence of cutoff and
turnover at least at the hydrogen-burning limit and likely at the
deuterium-burning limit. Our results therefore provide the key clues to a
census of very low mass stars and the IMF down to a few Jupiter-mass
regime for the first time in distance massive star forming regions.