The Co-evolution of Disk and Star in Embedded Stages: The Case of the Very Low-mass Protostar

Abstract

We have observed the CCH (N=3-2, J=7/2-5/2, F=4-3 and 3-2) and SO (6_7-5_6) emission at a 0"2 angular resolution toward the low-mass Class 0 protostellar source IRAS 15398-3359 with ALMA. The CCH emission traces the infalling-rotating envelope near the protostar with the outflow cavity extended along the northeast-southwest axis. On the other hand, the SO emission has a compact distribution around the protostar. The CCH emission is relatively weak at the continuum peak position, while the SO emission has a sharp peak there. Although the maximum velocity shift of the CCH emission is about 1 km s^-1 from the systemic velocity, a velocity shift higher than 2 km s^{-1} is seen for the SO emission. This high velocity component is most likely associated with the Keplerian rotation around the protostar. The protostellar mass is estimated to be 0.007^{+0.004}_{-0.003} from the velocity profile of the SO emission. With this protostellar mass, the velocity structure of the CCH emission can be explained by the model of the infalling-rotating envelope, where the radius of the centrifugal barrier is estimated to be 40 au from the comparison with the model. The disk mass evaluated from the dust continuum emission by assuming the dust temperature of 20 K-100 K is 0.1-0.9 times the stellar mass, resulting in the Toomre Q parameter of 0.4-5. Hence, the disk structure may be partly unstable. All these results suggest that a rotationally-supported disk can be formed in the earliest stages of the protostellar evolution.

References in corpus (38)

• Protoplanetary Disks and Their Evolution
• Evolution of protoplanetary disks: Constraints from DM Tauri and GM Aurigae
• A 0.2 solar mass protostar with a Keplerian disk in the very young L1527 IRS system
• Water in star-forming regions with Herschel (WISH): II. Evolution of 557 GHz 110-101 emission in low-mass protostars
• Effect of episodic accretion on the structure and the lithium depletion of low-mass stars and planet-hosting stars
• A Keplerian disk around a Class 0 source: ALMA observations of VLA1623A
• Collapse of a Molecular Cloud Core to Stellar Densities: The First Three-Dimensional Calculations
• Formation of a Keplerian disk in the infalling envelope around L1527 IRS: transformation from infalling motions to Kepler motions
• Hipparcos distances of Ophiuchus and Lupus cloud complexes
• Signs of Early-Stage Disk Growth Revealed with ALMA
• Recurrent Planet Formation and Intermittent Protostellar Outflows Induced by Episodic Mass Accretion
• Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA
• Emergence of Protoplanetary Disks and Successive Formation of Gaseous Planets by Gravitational Instability
• A recent accretion burst in the low-mass protostar IRAS 15398-3359: ALMA imaging of its related chemistry
• Decoupling of Magnetic Fields in Collapsing Protostellar Envelopes and Disk Formation and Fragmentation
• Formation and Atmosphere of Complex Organic Molecules of the HH 212 Protostellar Disk
• The potential for Earth-mass planet formation around brown dwarfs
• APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: IV. Mechanical and radiative feedback
• A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• ALMA Results of the Pseudodisk, Rotating disk, and Jet in Continuum and HCO+ in the Protostellar System HH 212
• Unveiling the Evolutionary Sequence from Infalling Envelopes to Keplerian Disks around Low-Mass Protostars
• SMA observations of young disks: separating envelope, disk, and stellar masses in class I YSOs
• 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?
• Disk and Envelope Structure in Class 0 Protostars: I. The Resolved Massive Disk in Serpens FIRS 1
• A Substellar-Mass Protostar and its Outflow of IRAS 15398-3359 Revealed by Subarcsecond-Resolution Observations of H${}_2$CO and CCH
• The impact of the Hall effect during cloud core collapse:implications for circumstellar disk evolution
• Molecular outflow launched beyond the disk edge
• Vertical Structure of the Transition Zone from Infalling Rotating Envelope to Disk in the Class 0 Protostar, IRAS04368+2557
• Transition from the Infalling Envelope to the Keplerian Disk around L1551 IRS 5
• ALMA observations of the kinematics and chemistry of disc formation
• ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks
• Dense and warm molecular gas in the envelopes and outflows of southern low-mass protostars
• Evaporation of grain-surface species by shock waves in proto-planetary disk
• Interplay between chemistry and dynamics in embedded protostellar disks
• A young bipolar outflow from IRAS 15398-3359
• Water around IRAS15398-3359 observed with ALMA
• A Rotating Disk in the HH 111 Protostellar System

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• The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars
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• 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
• FAUST II. Discovery of a Secondary Outflow in IRAS 15398-3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?
• Origin of Misalignments: Protostellar Jet, Outflow, Circumstellar Disc, and Magnetic Field
• Diagnosing FUor-like Sources: The Parameter Space of Viscously Heated Disks in the Optical and Near-IR
• Sulfur-Bearing Species Tracing the Disk/Envelope System in the Class I Protostellar Source Elias 29
• Substructures in the Disk-Forming Region of the Class 0 Low-Mass Protostellar Source IRAS 16293-2422 Source A on a 10 au Scale
• Chemical evolution during the formation of a protoplanetary disk
• Different Modes of Star Formation II: Gas Accretion Phase of Initially Subcritical Star-Forming Clouds
• Molecular Distributions of the Protostellar Envelope and the Outflow of IRAS 15398-3359: Principal Component Analysis
• FAUST VII. Detection of A Hot Corino in the Prototypical Warm Carbon-Chain Chemistry Source IRAS 15398-3359
• FERIA: Flat Envelope Model with Rotation and Infall under Angular Momentum Conservation
• Growth of Magnetorotational Instability in Circumstellar Disks around Class 0 Protostars
• Physical conditions for dust grain alignment in Class 0 protostellar cores I. Observations of dust polarization and molecular irradiation tracers
• Protostellar disks subject to infall: a one-dimensional inviscid model and comparison with ALMA observations
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Synthetic Observations of the Infalling Rotating Envelope: Links between the Physical Structure and Observational Features
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• The kinematics of the magnetised protostellar core IRAS15398-3359
• ALMA Band 9 CO(6--5) Reveals a Warm Ring Structure Associated with the Embedded Protostar in the Cold Dense Core MC 27/L1521F
• Substellar candidates at the earliest stages: the SUCANES database