The specific angular momentum radial profile in dense cores: improved initial conditions for disk formation

Abstract

The determination of the specific angular momentum radial profile, $j(r)$, in the early stages of star formation is crucial to constrain star and circumstellar disk formation theories. The specific angular momentum is directly related to the largest Keplerian disk possible, and it could constrain the angular momentum removal mechanism. We determine $j(r)$ towards two Class 0 objects and a first hydrostatic core candidate in the Perseus cloud, which is consistent across all three sources and well fit with a single power-law relation between 800 and 10,000\,au: $j_{fit}(r)=10^{-3.60\pm 0.15}{\left(r/\text{1,000au}\right)}^{1.80\pm 0.04}$ km s${}^{-1}$ pc. This power-law relation is in between solid body rotation ($\propto r^2$) and pure turbulence ($\propto r^{1.5}$). This strongly suggests that even at 1,000\,au, the influence of the dense core's initial level of turbulence or the connection between core and the molecular cloud is still present. The specific angular momentum at 10,000\,au is $\approx 3\times$ higher than previously estimated, while at 1,000\,au it is lower by $2\times$. We do not find a region of conserved specific angular momentum, although it could still be present at a smaller radius. We estimate an upper limit to the largest Keplerian disk radius of 60\,au, which is small but consistent with published upper limits. Finally, these results suggest that more realistic initial conditions for numerical simulations of disk formation are needed. Some possible solutions include: a) use a larger simulation box to include some level of driven turbulence or connection to the parental cloud, or b) incorporate the observed $j(r)$ to setup the dense core kinematics initial conditions.

Accepted to ApJ, 13 pages, 7 figures

References in corpus (24)

• Observing the gas temperature drop in the high-density nucleus of L 1544
• Magnetic Braking and Protostellar Disk Formation: The Ideal MHD Limit
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• Radiation Magnetohydrodynamic Simulations of Protostellar Collapse: Non-Ideal Magnetohydrodynamic Effects and Early Formation of Circumstellar Disks
• Magnetic processes in a collapsing dense core. II Fragmentation. Is there a fragmentation crisis ?
• The Gould's Belt Distances Survey (GOBELINS). V. Distances and Kinematics of the Perseus molecular cloud
• Characterizing young protostellar disks with the CALYPSO IRAM-PdBI survey: large Class 0 disks are rare
• Signs of Early-Stage Disk Growth Revealed with ALMA
• Decoupling of Magnetic Fields in Collapsing Protostellar Envelopes and Disk Formation and Fragmentation
• Mapping Distances Across the Perseus Molecular Cloud Using CO Observations, Stellar Photometry, and Gaia DR2 Parallax Measurements
• Observations of Infalling and Rotational Motions on a 1,000-AU Scale around 17 Class 0 and 0/I Protostars: Hints of Disk Growth and Magnetic Braking?
• OVRO N2H+ Observations of Class 0 Protostars: Constraints on the Formation of Binary Stars
• On the reliability of protostellar disc mass measurements and the existence of fragmenting discs
• The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). V. 18 Candidate Disks around Class 0 and I Protostars in the Perseus Molecular Cloud
• The central 1000 AU of a pre-stellar core revealed with ALMA. I. 1.3 mm continuum observations
• ALMA observations of the kinematics and chemistry of disc formation
• On the Role of Pseudodisk Warping and Reconnection in Protostellar Disk Formation in Turbulent Magnetized Cores
• ALMA observations of the very young Class 0 protostellar system HH 211-mms: a 30-au dusty disk with a disk-wind traced by SO?
• A Pseudodisk Threaded with a Toroidal and Pinched Poloidal Magnetic Field Morphology in the HH 211 Protostellar System
• The Origins of Protostellar Core Angular Momenta
• The core and stellar mass functions in massive collapsing filaments
• Testing protostellar disk formation models with ALMA observations
• On estimating angular momenta of infalling protostellar cores from observations

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• PRODIGE -- Envelope to disk with NOEMA I. A 3000 au streamer feeding a Class I protostar
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• Accretion Flows or Outflow Cavities? Uncovering the Gas Dynamics around Lupus 3-MMS
• Kinematics and stability of high-mass protostellar disk candidates at sub-arcsecond resolution -- Insights from the IRAM NOEMA large program CORE
• ALMA observations of envelopes around first hydrostatic core candidates
• Investigating the Complex Velocity Structures within Dense Molecular Cloud Cores with GBT-Argus
• Rotating filament in Orion B: Do cores inherit their angular momentum from their parent filament?
• Droplets II: Internal Velocity Structures and Potential Rotational Motions in Pressure-dominated Coherent Structures
• Protostellar disk formation by a non-rotating, non-axisymmetric collapsing cloud: model and comparison with observations
• Constraints on the (re-)orientation of star-disk systems through infall
• The role of magnetic fields in the formation of multiple massive stars
• Which Part of Dense Cores Feeds Material to Protostars?: The Case of L1489 IRS
• Evolution of the Angular Momentum of Molecular Cloud Cores Formed from Filament Fragmentation
• Similar levels of deuteration in the pre-stellar core L1544 and the protostellar core HH211
• Gas kinematics around filamentary structures in the Orion B cloud
• Evolution of the angular momentum during gravitational fragmentation of molecular clouds
• Alignment of dense molecular core morphology and velocity gradients with ambient magnetic fields
• No impact of core-scale magnetic field, turbulence, or velocity gradient on sizes of protostellar disks in Orion A
• Evolution and Kinematics of Protostellar Envelopes in the Perseus Molecular Cloud
• VLA and NOEMA view of the Bok Globule CB 17: the starless nature of a proposed FHSC candidate
• Confirmation of the outflow in L1451-mm: SiO line and CH${}_3$OH maser detections
• Which molecule traces what: chemical diagnostics of protostellar sources
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