2005/11/29 by K. L. Luhman, L. Adame, Lucia Adame +6 · 6 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/498868
published as Astrophys.J.635:L93-L96,2005 · 5 pages, accepted to Astrophysical Journal Letters
arxiv created 2005/11/29 · openalex publication_date 2005/11/29 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
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 8 M J , placing it fully within the mass range observed for extrasolar planetary companions ( M ≲ 15 M J ). 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.