Bibcode
Burgess, A. S. M.; Moraux, E.; Bouvier, J.; Marmo, C.; Albert, L.; Bouy, H.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 508, Issue 2, 2009, pp.823-831
Fecha de publicación:
12
2009
Revista
Número de citas
51
Número de citas referidas
42
Descripción
Context: The determination of the lower-end of the initial mass function
(IMF) provides strong constraints on star formation theories.
Aims: We report here on a search for isolated planetary-mass objects in
the 3 Myr-old star-forming region IC 348. Methods: Deep,
narrowband CH4off and CH4on images were obtained with CFHT/WIRCam over
0.11 sq. deg. in the central part of IC 348 to identify young T-dwarfs
from their 1.6 μm methane absorption bands. Results: We report
three faint T-dwarf candidates with CH4on-CH4off colours >0.4 mag.
Extinction was estimated for each candidate and lies in the range
AV ~ 5-12 mag. Comparisons with T-dwarf spectral models, and
colour/colour and colour/magnitude diagrams, reject two of the three
candidates because of their extreme z'-J blueness. The one remaining
object is not thought to be a foreground field dwarf because of a number
density argument and also its strong extinction AV ~ 12 mag,
or thought to be a background field T-dwarf which would be expected to
be much fainter. Models and diagrams give this object a preliminary T6
spectral type. Conclusions: With a few Jupiter masses, the young
T-dwarf candidate reported here is potentially amongst the youngest,
lowest mass objects detected in a star-forming region so far. Its
frequency is consistent with the extrapolation of current lognormal IMF
estimates down to the planetary mass domain.
Based on observations obtained with WIRCam, a joint project of CFHT,
Taiwan, Korea, Canada, France, at the Canada-France-Hawaii Telescope
(CFHT) which is operated by the National Research Council (NRC) of
Canada, the Institute National des Sciences de l'Univers of the Centre
National de la Recherche Scientifique of France, and the
“University of Hawaii. Research supported by the Marie Curie
Research Training Network CONSTELLATION” under grant no.
MRTN-CT-2006-035890.