Brown dwarf disks with ALMA: evidence for truncated dust disks in Ophiuchus

Abstract

The study of the properties of disks around young brown dwarfs can provide important clues on the formation of these very low-mass objects and on the possibility of forming planetary systems around them. The presence of warm dusty disks around brown dwarfs is well known, based on near- and mid-infrared studies. High angular resolution observations of the cold outer disk are limited; we used ALMA to attempt a first survey of young brown dwarfs in the $\rho$-Oph star-forming region. All 17 young brown dwarfs in our sample were observed at 890 $\mu$m in the continuum at $\sim 0.{}^{\prime \prime }5$ angular resolution. The sensitivity of our observations was chosen to detect $\sim 0.5$ M${}_{\oplus }$ of dust. We detect continuum emission in 11 disks ($\sim 65$\%\ of the total), and the estimated mass of dust in the detected disks ranges from $\sim 0.5$ to $\sim 6$ M${}_{\oplus }$. These disk masses imply that planet formation around brown dwarfs may be relatively rare and that the supra-Jupiter mass companions found around some brown dwarfs are probably the result of a binary system formation. We find evidence that the two brightest disks in $\rho$-Oph have sharp outer edges at R<~25 AU, in contrast to disks around Taurus brown dwarfs. This difference may suggest that the different environment in $\rho$-Oph may lead to significant differences in disk properties. A comparison of the M${}_{disk}$/M${}_{\ast }$ ratio for brown dwarf and solar-mass systems also shows a possible deficit of mass in brown dwarfs, which could support the evidence for dynamical truncation of disks in the substellar regime. These findings are still tentative and need to be put on firmer grounds by studying the gaseous disks around brown dwarfs and by performing a more systematic and unbiased survey of the disk population around the more massive stars.

12 pages, A&A in press

References in corpus (14)

• Gas- and dust evolution in protoplanetary disks
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• Accretion in the Rho-Oph pre-main sequence stars
• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• Structure and evolution of pre-main sequence circumstellar disks
• The Impact of Dust Evolution and Photoevaporation on Disk Dispersal
• The potential for Earth-mass planet formation around brown dwarfs
• Brown dwarf disks with ALMA
• The properties of discs around planets and brown dwarfs as evidence for disc fragmentation
• X-Shooter study of accretion in $\rho$-Ophiucus: very low-mass stars and brown dwarfs
• Old pre-main-sequence Stars: Disc reformation by Bondi-Hoyle accretion
• Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes
• Herschel/PACS view of disks around low-mass stars and brown dwarfs in the TW Hya association
• The disk around the brown dwarf KPNO Tau 3

Cited by in corpus (48)

• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• On the diversity and statistical properties of protostellar discs
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Physical properties of dusty protoplanetary disks in Lupus: evidence for viscous evolution?
• Measurement of Circumstellar Disk Sizes in the Upper Scorpius OB Association with ALMA
• A rich population of free-floating planets in the Upper Scorpius young stellar association
• An ALMA survey of DCN/H${}^{13}$CN and DCO${}^{+}$/H${}^{13}$CO${}^{+}$ in protoplanetary disks
• ALMA survey of Class II protoplanetary disks in Corona Australis: a young region with low disk masses
• The protoplanetary disk population in the rho-Ophiuchi region L1688 and the time evolution of Class II YSOs
• Pebble-driven Planet Formation around Very Low-mass Stars and Brown Dwarfs
• Far-infrared to millimeter data of protoplanetary disks: dust growth in the Taurus, Ophiuchus, and Chamaeleon I star-forming regions
• Measuring the ratio of the gas and dust emission radii of protoplanetary disks in the Lupus star-forming region
• GJ 273: On the formation, dynamical evolution and habitability of a planetary system hosted by an M dwarf at 3.75 parsec
• Demographics of disks around young very low-mass stars and brown dwarfs in Lupus
• An ALMA and MagAO Study of the Substellar Companion GQ Lup B
• The Taurus Boundary of Stellar/Substellar (TBOSS) Survey II. Disk Masses from ALMA Continuum Observations
• ALMA Survey of Lupus Class III Stars: Early Planetesimal Belt Formation and Rapid Disk Dispersal
• On the underestimation of dust mass in protoplanetary disks: Effects of disk structure and dust properties
• First millimeter detection of the disk around a young, isolated, planetary-mass object
• ALMA Observations of the Young Substellar Binary System 2M1207
• Testing external photoevaporation in the $\sigma$-Orionis cluster with spectroscopy and disk mass measurements
• The origin of free-floating planets
• Brown dwarf disks with Herschel: Linking far-infrared and (sub)-mm fluxes
• The effects of dust evolution on disks in the mid-IR
• OGLE-2015-BLG-1771Lb: A Microlens Planet Orbiting an Ultracool Dwarf?
• Disk Masses and Dust Evolution of Protoplanetary Disks Around Brown Dwarfs
• A wide planetary-mass companion to a young low-mass brown dwarf in Ophiuchus
• A Detached Protostellar Disk around a $\sim$0.2$M_{\odot }$ protostar in a Possible Site of a Multiple Star Formation in a Dynamical Environment in Taurus
• Planet gap opening across stellar masses
• Spatially correlated stellar accretion in the Lupus star forming region: Evidence for ongoing infall from the interstellar medium
• Millimeter Spectral Indices and Dust Trapping By Planets in Brown Dwarf Disks
• On the time evolution of the $M_{\mathrm{d}}-M_{\star }$ and $\dot{M}-M_{\star }$ correlations for protoplanetary discs: the viscous timescale increases with stellar mass
• Modeling the Protoplanetary Disks of Two Brown Dwarfs in the Taurus Molecular Cloud
• Disks around young planetary-mass objects: Ultradeep Spitzer imaging of NGC1333
• A giant planet shaping the disk around the very low-mass star CIDA 1
• VLA observations of the disk around the young brown dwarf 2MASS J044427+2512
• Modeling snowline locations in protostars: The impact of the structure of protostellar cloud cores
• An SMA Continuum Survey of Circumstellar Disks in the Serpens Star-Forming Region
• ALMA observations of the early stages of substellar formation in the Lupus 1 and 3 molecular clouds
• Physical properties of terrestrial planets and water delivery in the habitable zone using N-body simulations with fragmentation
• Planetesimal formation via the streaming instability in simulations of infall dominated young disks
• Lost in space: companions' fatal dance around massive dying stars
• MINDS. Cha Hα 1, a brown dwarf with a hydrocarbon-rich disk
• The evolution of the $M_{\mathrm{d}}-M_{\star }$ and $\dot{M}-M_{\star }$ correlations traces protoplanetary disc dispersal
• FAUST. XXVIII. High-Resolution ALMA Observations of Class 0/I Disks: Structure, Optical Depths, and Temperatures
• New constraints on the presence of debris disks around G 196-3 B and VHS J125601.92-125723.9 b
• A deep staring campaign in the Sigma Orionis cluster. Variability in substellar members
• Disk fraction among free-floating planetary-mass objects in Upper Scorpius