Year: 2009
Type: article
Abstract: 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 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.
Source: Astronomy and Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2117774741