Protostellar disks subject to infall: a one-dimensional inviscid model and comparison with ALMA observations

Abstract

A new one-dimensional, inviscid, and vertically integrated disk model with prescribed infall is presented. The flow is computed using a second-order shock-capturing scheme. Included are vertical infall, radial infall at the outer radial boundary, radiative cooling, stellar irradiation, and heat addition at the disk-surface shock. Simulation parameters are chosen to target the L1527 IRS disk which has been observed using ALMA (Atacama Large Millimeter Array). The results give an outer envelope of radial infall and $u_{\varphi }\propto 1/r$ which encounters a radial shock at $r_{\mathrm{shock}}\sim 1.5\times$ the centrifugal radius ($r_{\mathrm{c}}$) across which the radial velocity is greatly reduced and the gas temperature rises from a pre-shock value of $\approx 25$ K to $\approx 180$ K over a spatially thin region calculated using a separate shock structure code. At $r_{\mathrm{c}}$, the azimuthal velocity $u_{\varphi }$ transitions from being $\propto 1/r$ to being nearly Keplerian. These results qualitatively agree with recent ALMA observations which indicate a radial shock where SO is sublimated as well as a transition from a $u_{\varphi }\sim 1/r$ region to a Keplerian inner disk. However, in one set of observations, the position-velocity map of cyclic-C${}_3$H${}_2$, together with a certain ballistic maximum velocity relation, has suggested that the radial shock coincides with a ballistic centrifugal barrier, which places the shock at $r_{\mathrm{shock}}=0.5r_{\mathrm{c}}$, i.e, inward of $r_{\mathrm{c}}$, rather than outward as given by our simulations. It is argued that radial velocity plots from previous magnetic rotating-collapse simulations also indicate that the radial shock is located outward of $r_{\mathrm{c}}$. The discrepancy with observations is analyzed and discussed, but remains unresolved.

arXiv commentOriginally, we incorrectly took Semenov etal. opacities to be m${}^2$ per gm of dust rather than gas. Thus our opacities were too low by a factor of 100. Making the correction reduced the temperature across the shock but left velocities and densities nearly unchanged. To account for SO sublimation in L1527 observed by ALMA, we performed a separate 1D shock calculation including non-LTE effects

References in corpus (29)

• Rosseland and Planck Mean Opacities for Protoplanetary Discs
• Evolution of protoplanetary disks: Constraints from DM Tauri and GM Aurigae
• The chemical history of molecules in circumstellar disks. I. Ices
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• Formation Process of the Circumstellar Disk: Long-term Simulations in the Main Accretion Phase of Star Formation
• Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA
• Protostellar Disk Formation Enabled by Removal of Small Dust Grains
• ALMA Observations of the Transition from Infall Motion to Keplerian Rotation around the Late-phase Protostar TMC-1A
• ALMA Observations of Infalling Flows toward the Keplerian Disk around the Class I Protostar L1489 IRS
• Episodic Accretion in Young Stars
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• The Role of Magnetic Fields in Protostellar Outflows and Star Formation
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. III. Substructures in Protostellar Disks
• ALMA Observations of the Protostar L1527 IRS: Probing Details of the Disk and the Envelope Structures
• Formation and Evolution of Disks around Young Stellar Objects
• Vertical Structure of the Transition Zone from Infalling Rotating Envelope to Disk in the Class 0 Protostar, IRAS04368+2557
• Subarcsecond Analysis of Infalling-Rotating Envelope around the Class I Protostar IRAS 04365+2535
• Analytic solutions to the accretion of a rotating finite cloud towards a central object I. Newtonian approach
• Geometric and Kinematic Structure of the Outflow/Envelope System of L1527 Revealed by Subarcsecond-resolution Observation of CS
• Disk structure around the Class I protostar L1489 IRS revealed by ALMA: a warped disk system
• Chemical and Physical Picture of IRAS 16293-2422 Source B at a Sub-arcsecond Scale Studied with ALMA
• The Co-evolution of Disk and Star in Embedded Stages: The Case of the Very Low-mass Protostar
• Sub-Keplerian accretion onto circumstellar disks
• Substructure Formation in a Protostellar Disk of L1527 IRS
• The Interplay between Ambipolar Diffusion and Hall Effect on Magnetic Field Decoupling and Protostellar Disc Formation
• Evaporation of grain-surface species by shock waves in proto-planetary disk
• Water and interstellar complex organics associated with the HH 212 protostellar disc - On disc atmospheres, disc winds, and accretion shocks
• Magnetic field and early evolution of circumstellar disks
• Protoplanetary disk formation from the collapse of a prestellar core

Cited by in corpus (4)

• Early Planet Formation in Embedded Disks (eDisk) III: A first high-resolution view of sub-mm continuum and molecular line emission toward the Class 0 protostar L1527 IRS
• Synthetic Observations of the Infalling Rotating Envelope: Links between the Physical Structure and Observational Features
• Modelling the Break in the Specific Angular Momentum within the Envelope-Disk Transition Zone
• Semianalytical Accretion-Tracer Emission: Forming Planets Are Intrinsically Faint