Pebbles in an Embedded Protostellar Disk: The Case of CB26

Abstract

Planetary cores are thought to form in proto-planetary disks via the growth of dusty solid material. However, it is unclear how early this process begins. We study the physical structure and grain growth in the edge-on disk that surrounds the ~1 Myr old low-mass (~0.55 Msun) protostar embedded in the Bok Globule CB26 to examine how much grain growth has already occurred in the protostellar phase. We combine the SED between 0.9 $\mu$m and 6.4 cm with high angular resolution continuum maps at 1.3, 2.9, and 8.1 mm, and use the radiative transfer code RADMC-3D to conduct a detailed modelling of the dust emission from the disk and envelope of CB 26. We infer inner and outer disk radii of around 16 au and 172$\pm$22 au, respectively. The total gas mass in the disk is ~0.076 Msun, which amounts to ~14% of the mass of the central star. The inner disk contains a compact free-free emission region, which could be related to either a jet or a photoevaporation region. The thermal dust emission from the outer disk is optically thin at mm wavelengths, while the emission from the inner disk midplane is moderately optically thick. Our best-fit radiative transfer models indicate that the dust grains in the disk have already grown to pebbles with diameters of the order of 10 cm in size. Residual 8.1 mm emission suggests the presence of even larger particles in the inner disk. For the optically thin mm dust emission from the outer disk, we derive a mean opacity slope of 0.6$\pm$0.4, which is consistent with the presence of large dust grains. The presence of cm-sized bodies in the CB 26 disk indicates that solids grow rapidly already during the first million years in a protostellar disk. It is thus possible that Class II disks are already seeded with large particles and may contain even planetesimals.

arXiv commentAccepted for publication in A&A; 17 pages, 14 figures

References in corpus (52)

• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• Protoplanetary Disks and Their Evolution
• Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
• The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 microns Using GLIMPSE Data
• The Mass Dependence Between Protoplanetary Disks and their Stellar Hosts
• Gas- and dust evolution in protoplanetary disks
• The Submillimeter Array
• ALMA Survey of Lupus Protoplanetary Disks I: Dust and Gas Masses
• A Steeper than Linear Disk Mass-Stellar Mass Scaling Relation
• Dust Properties of Protoplanetary Disks in the Taurus-Auriga Star Forming Region from Millimeter Wavelengths
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. A Statistical Characterization of Class 0 and I Protostellar Disks
• On the Role of Disks in the Formation of Stellar Systems: A Numerical Parameter Study of Rapid Accretion
• The effect of cooling on the global stability of self-gravitating protoplanetary discs
• A 0.2 solar mass protostar with a Keplerian disk in the very young L1527 IRS system
• PROSAC: A Submillimeter Array survey of low-mass protostars. II. The mass evolution of envelopes, disks, and stars from the Class 0 through I stages
• Millimeter-wave polarization of protoplanetary disks due to dust scattering
• Large dust particles in disks around T Tauri stars
• Dust grain growth in rho-Ophiuchi protoplanetary disks
• Large grains in the disk of CQ Tau
• One Solution to the Mass Budget Problem for Planet Formation: Optically Thick Disks with Dust Scattering
• Dust masses of young disks: constraining the initial solid reservoir for planet formation
• A multi-wavelength analysis for interferometric (sub-)mm observations of protoplanetary disks: radial constraints on the dust properties and the disk structure
• Probing dust grain evolution in IM Lupi's circumstellar disc. Multi-wavelength observations and modelling of the dust disc
• The Radial Distribution of Dust Particles in the HL Tau Disk from ALMA and VLA Observations
• The Circumstellar Disk of the Butterfly Star in Taurus
• The earliest phases of star formation - A Herschel key project. The thermal structure of low-mass molecular cloud cores
• Towards Planetesimals in the Disk around TW Hya: 3.5 centimeter Dust Emission
• Can giant planets form by gravitational fragmentation of discs?
• The anomalously low (sub)millimeter spectral indices of some protoplanetary disks may be explained by dust self-scattering
• Observations of T Tauri Disks at Sub-AU Radii: Implications for Magnetospheric Accretion and Planet Formation
• A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks
• Dynamics of Circumstellar Disks II: Heating and Cooling
• Rotating molecular outflows: the young T Tauri star in CB26
• Modeling the Resolved Disk Around the Class 0 Protostar L1527
• Spiral Arms in Disks: Planets or Gravitational Instability?
• From infall to rotation around young stellar objects: A transitional phase with a 2000 AU radius contracting disk?
• Free-free Emission and Radio Recombination Lines from Photoevaporating Disks
• Looking into the hearts of Bok globules: MM and submm continuum images of isolated star-forming cores
• Unveiling the physical conditions of the youngest disks: A warm embedded disk in L1527
• The radial effective temperature distribution of steady-state, mass-losing accretion disks
• The circumstellar disc in the Bok globule CB 26: Multi-wavelength observations and modelling of the dust disc and envelope
• A dust and gas cavity in the disc around CQ Tau revealed by ALMA
• An Ionized Outflow from AB Aur, a Herbig Ae Star with a Transitional Disk
• A young protoplanetary disk in the Bok globule CB26?
• The properties of the inner disk around HL Tau: Multi-wavelength modeling of the dust emission
• Multiwavelength studies of the gas and dust disc of IRAS 04158+2805
• Measuring protoplanetary disk gas surface density profiles with ALMA
• Dust in the Interplanetary Medium
• High-Resolution NIR Observations of the Circumstellar Disk System in the Bok Globule CB 26
• Imaging the water snowline in a protostellar envelope with H${}^{13}$CO${}^{+}$
• Sub-millimeter non-contaminated detection of the disk around TWA\,7 by ALMA
• Structure of CB 26 Protoplanetary Disk Derived from Millimeter Dust Continuum Maps

Cited by in corpus (5)

• Modest dust settling in the IRAS04302+2247 Class I protoplanetary disk
• Millimeter-sized Dust Grains Appear Surviving the Water-sublimating Temperature in the Inner 10 au of the FU Ori Disk
• Mixing is easy: New insights for cosmochemical evolution from pre-stellar core collapse
• A resolved rotating disk wind from a young T Tauri star in the Bok globule CB26
• A disk-wind driving the rotating molecular outflow in CB 26