Spitzer Identification of the Least Massive Known Brown Dwarf with a Circumstellar Disk

Abstract

Using the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope, we have obtained mid-infrared photometry of the least massive known brown dwarf in the Chamaeleon I star-forming region. For this young brown dwarf, OTS 44, we have constructed a spectral energy distribution (SED) from 0.8-8 um by combining the measurements at 3.6, 4.5, 5.8, and 8.0 um from IRAC with ground-based photometry at I, J, H, and K. The resulting SED for OTS 44 exhibits significant excess emission longward of 3 um relative to the SED expected from the photosphere of the brown dwarf. We have successfully modeled the source of this excess emission in terms of an irradiated viscous accretion disk with M'<=10^-10 M_sun/year. With a spectral type of M9.5 and a mass of ~15 M_Jup, OTS 44 is now the coolest and least massive brown dwarf observed to have a circumstellar disk. These measurements demonstrate that disks exist around brown dwarfs even down to the deuterium burning mass limit and the approximate upper mass limit of extrasolar planetary companions.

arXiv comment9 pages, 1 figure

References in corpus (37)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• A Giant Planet Candidate near a Young Brown Dwarf
• Accretion Disks around Young Objects. I. The Detailed Vertical Structure
• A Census of the Young Cluster IC 348
• Very Low Mass Stars and Brown Dwarfs in Taurus-Auriga
• Evidence for a developing gap in a 10 Myr old protoplanetary disk
• Accretion Disks Around Young Objects. III. Grain Growth
• Accretion Disks Around Young Objects. II. Tests of Well-Mixed Models with Ism Dust
• Accretion in Young Stellar/Substellar Objects
• Accretion in Brown Dwarfs: an Infrared View
• Young Low-Mass Stars and Brown Dwarfs in IC 348
• Brown Dwarfs and the TW Hya Association
• New Brown Dwarfs and an Updated Initial Mass Function in Taurus
• The Structure and Emission of the Accretion Shock in T Tauri Stars II: the Ultraviolet Continuum Emission
• Infrared L Band Observations of the Trapezium Cluster: A Census of Circumstellar Disks and Candidate Protostars
• Evidence for a T Tauri Phase in Young Brown Dwarfs
• New Low-Mass Members of the Taurus Star-Forming Region
• A Disk Census for Young Brown Dwarfs
• Evidence for Circumstellar Disks around Young Brown Dwarfs in the Trapezium Cluster
• Exploring Brown Dwarf Disks
• Exploring Brown Dwarf Disks in rho Oph
• First Detection of Millimeter Dust Emission from Brown Dwarf Disks
• Magellan Echelle Spectroscopy of TW Hydrae Brown Dwarfs
• Four Brown Dwarfs in the Taurus Star-Forming Region
• A Survey for Circumstellar Disks Around Young Substellar Objects
• Spherically symmetric model atmospheres for low mass pre-Main Sequence stars with effective temperatures between 2000 and 6800 K
• Evolution of Young Brown Dwarf Disks in the Mid-Infrared
• The First Detailed Look at a Brown Dwarf Disk
• Deep 3.8 micron Observations of the Trapezium Cluster
• Grain growth and dust settling in a brown dwarf disk: Gemini/T-ReCS observations of CFHT-BD-Tau 4
• Flared Disks and Silicate Emission in Young Brown Dwarfs
• A Young Very Low-Mass Object surrounded by warm dust
• Spectroscopic Confirmation of the Least Massive Known Brown Dwarf in Chamaeleon
• Discovery of a very cool object with extraordinarily strong H(alpha) emission
• Activity at the Deuterium-Burning Mass Limit in Orion

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• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• IRAC Observations of Taurus Pre-Main Sequence Stars
• The Disk Population of the Chamaeleon I Star-Forming Region
• A library of near-infrared integral field spectra of young M-L dwarfs
• Young, Low-Mass Brown Dwarfs with Mid-Infrared Excesses
• Discovery of a Planetary-Mass Brown Dwarf with a Circumstellar Disk
• The young population of the Chamaeleon II dark cloud
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds.X. The Chamaeleon II Pre-Main Sequence Population as Observed With IRAC and MIPS
• The Disk Fractions of Brown Dwarfs in IC 348 and Chamaeleon I
• A Herschel Survey of Cold Dust in Disks Around Brown Dwarfs and Low-Mass Stars
• A Comprehensive View of Circumstellar Disks in Chamaeleon I: Infrared Excess, Accretion Signatures and Binarity
• Exploring the Role of Sub-micron Sized Dust Grains in the Atmospheres of Red L0 - L6 Dwarfs
• OTS44: Disk and accretion at the planetary border
• First Fruits of the Spitzer Space Telescope: Galactic and Solar System Studies
• Deep Near-Infrared Imaging of the rho Oph Cloud Core: Clues to the Origin of the Lowest-Mass Brown Dwarfs
• Spitzer Observations of two TW Hydrae Association Brown Dwarfs
• BANYAN. VIII. New Low-Mass Stars and Brown Dwarfs with Candidate Circumstellar Disks
• First millimeter detection of the disk around a young, isolated, planetary-mass object
• Near-infrared Linear Polarization of Ultracool Dwarfs
• Spitzer Observations of Long Term Infrared Variability Among Young Stellar Objects in Chamaeleon I
• Spectroscopy of Young Planetary Mass Candidates with Disks
• Nature of Infrared Sources in 11 micron Selected Sample from Early Data of the AKARI North Ecliptic Pole Deep Survey
• First Ultraviolet Spectrum of a Brown Dwarf: Evidence for H_2 Fluorescence and Accretion
• The First Brown Dwarf/Planetary-Mass Object in the 32 Orionis Group
• A homogeneous analysis of disks around brown dwarfs
• A WFI survey in the Chamaeleon II dark cloud
• A mid-infrared study of very low mass stars and brown dwarfs in Upper Scorpius
• On the properties of discs around accreting brown dwarfs
• Microlensing planet detection via geosynchronous and low Earth orbit satellites
• Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30
• Microlensing due to free-floating moon-planet systems
• Astrophysics in 2005
• Disk fraction among free-floating planetary-mass objects in Upper Scorpius
• Searching for proto-brown dwarfs: Extending near IR spectroscopy of protostars below the hydrogen burning limit
• XMM-Newton follow-up of two eROSITA X-ray binary candidates