Young, Low-Mass Brown Dwarfs with Mid-Infrared Excesses

Abstract

We have combined new I, J, H, and Ks imaging of portions of the Chamaeleon II, Lupus I, and Ophiuchus star-forming clouds with 3.6 to 24 micron imaging from the Spitzer Legacy Program, "From Molecular Clouds to Planet Forming Disks", to identify a sample of 19 young stars, brown dwarfs and sub-brown dwarfs showing mid-infrared excess emission. The resulting sample includes sources with luminosities of 0.5>log(L/Lsun)>-3.1. Six of the more luminous sources in our sample have been previously identified by other surveys for young stars and brown dwarfs. Five of the sources in our sample have nominal masses at or below the deuterium burning limit (~12 M_J). Over three decades in luminosity, our sources have an approximately constant ratio of excess to stellar luminosity. We compare our observed SEDs to theoretical models of a central source with a passive irradiated circumstellar disk and test the effects of disk inclination, disk flaring, and the size of the inner disk hole on the strength/shape of the excess. The observed SEDs of all but one of our sources are well fit by models of flared and/or flat disks.

35 pages, ApJ accepted

Cited by in corpus (24)

• The Stellar Population of the Chamaeleon I Star-Forming Region
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• The Disk Population of the Chamaeleon I Star-Forming Region
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. XI. Lupus Observed With IRAC and MIPS
• c2d Spitzer IRS Spectra of Disks around T Tauri Stars. III. [Ne II], [Fe I], and H_2 gas-phase lines
• The Wide Brown Dwarf Binary Oph 1622-2405 and Discovery of A Wide, Low Mass Binary in Ophiuchus (Oph 1623-2402): A New Class of Young Evaporating Wide Binaries?
• 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
• New Low-Mass Stars and Brown Dwarfs with Disks in the Chamaeleon I Star-Forming Region
• Very Low-Mass Objects in the Coronet Cluster: The Realm of the Transition Disks
• Substellar Objects in Nearby Young Clusters (SONYC): The bottom of the Initial Mass Function in NGC1333
• Contamination by field late-M, L and T dwarfs in deep surveys
• Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB
• Emission Line Variability of the Accreting Young Brown Dwarf 2MASSW J1207334-393254: From Hours to Years
• Spectroscopy of planetary mass brown dwarfs in Orion
• What is a planet?
• Oph 1622-2405: Not a Planetary-Mass Binary
• The transition disc frequency in M stars
• New Low-Mass Stars and Brown Dwarfs with Disks in Lupus
• New constraints on the membership of the T dwarf S Ori 70 in the sigma Orionis cluster
• Spectroscopy of Young Planetary Mass Candidates with Disks
• A WFI survey in the Chamaeleon II dark cloud
• Submillimeter Observations of the Young Low-Mass Object IRAS 04158+2805
• Infrared Spectroscopy of the Ultra Low Mass Binary Oph 162225-240515