• DOI:10.1086/498868
• Corpus ID: 11685964

Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk

@article{Luhman2005DiscoveryOA,
  title={Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk},
  author={K. L. Luhman and Lucia Adame and Paola d’Alessio and Nuria Calvet and Lee Hartmann and S. Thomas Megeath and Giovanni G. Fazio},
  journal={The Astrophysical Journal},
  year={2005},
  volume={635}
}

• K. Luhman, L. Adame, +4 authors G. Fazio
• Published 29 November 2005
• Physics, Geology
• The Astrophysical Journal

Using the Hubble Space Telescope, the 4 m Blanco Telescope at the Cerro Tololo Inter-American Observatory, and the Spitzer Space Telescope, we have performed deep imaging from 0.8 to 8 μm of the southern subcluster in the Chamaeleon I star-forming region. In these data, we have discovered an object, Cha 110913-773444, whose colors and magnitudes are indicative of a very low mass brown dwarf with a circumstellar disk. In a near-infrared spectrum of this source obtained with the Gemini Near-Infrared Spectrograph, the presence of strong steam absorption confirms its late-type nature (M9.5) while the shapes of the H- and K-band continua and the strengths of the Na I and K I lines demonstrate that it is a young, pre-main-sequence object rather than a field dwarf. A comparison of the bolometric luminosity of Cha 110913-773444 to the luminosities predicted by the evolutionary models of Chabrier & Baraffe and Burrows and coworkers indicates a mass of 8MJ, placing it fully within the mass range observed for extrasolar planetary companions (M 15MJ). The spectral energy distribution of this object exhibits mid-infrared excess emission at λ > 5 μm, which we have successfully modeled in terms of an irradiated viscous accretion disk with 10-12 M☉ yr-1. Cha 110913-773444 is now the least massive brown dwarf observed to have a circumstellar disk, and indeed is one of the least massive free-floating objects found to date. These results demonstrate that the raw materials for planet formation exist around free-floating planetary-mass bodies.