Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST. IV

Abstract

Chemical diversity of low-mass protostellar sources has so far been recognized, and environmental effects are invoked as its origin. In this context, observations of isolated protostellar sources without influences of nearby objects are of particular importance. Here, we report chemical and physical structures of the low-mass Class 0 protostellar source IRAS 16544$-$1604 in the Bok globule CB68, based on 1.3 mm ALMA observations at a spatial resolution of $\sim$70~au that were conducted as part of the large program FAUST. Three interstellar saturated complex organic molecules (iCOMs), CH${}_3$OH, HCOOCH${}_3$, and CH${}_3$OCH${}_3$, are detected toward the protostar. The rotation temperature and the emitting region size for CH${}_3$OH are derived to be $131\pm 11$~K and $\sim$10~au, respectively. The detection of iCOMs in close proximity to the protostar indicates that CB68 harbors a hot corino. The kinematic structure of the C${}^{18}$O, CH${}_3$OH, and OCS lines is explained by an infalling-rotating envelope model, and the protostellar mass and the radius of the centrifugal barrier are estimated to be $0.08-0.30$~$M_{\odot }$ and $<30$ au, respectively. The small radius of the centrifugal barrier seems to be related to the small emitting region of iCOMs. In addition, we detect emission lines of c-C${}_3$H${}_2$ and CCH associated with the protostar, revealing a warm carbon chain chemistry (WCCC) on a 1000~au scale. We therefore find that the chemical structure of CB68 is described by a hybrid chemistry. The molecular abundances are discussed in comparison with those in other hot corino sources and reported chemical models.

43 pages, 4 tables, 12 figures

References in corpus (63)

• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• Initial Performance of the NEOWISE Reactivation Mission
• Our astrochemical heritage
• A three-phase chemical model of hot cores: the formation of glycine
• The ALMA Protostellar Interferometric Line Survey (PILS): First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA
• Physical structure and CO abundance of low-mass protostellar envelopes
• The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). II. Multiplicity of Protostars in the Perseus Molecular Cloud
• Water in star-forming regions with Herschel (WISH): II. Evolution of 557 GHz 110-101 emission in low-mass protostars
• A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition
• Molecular Evolution and Star Formation: From Prestellar Cores to Protostellar Cores
• The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293-2422B
• Constraining the abundances of complex organics in the inner regions of solar-type protostars
• The Gould's Belt Distances Survey (GOBELINS) I. Trigonometric parallax distances and depth of the Ophiuchus complex
• Formation of complex organic molecules in hot molecular cores through nondiffusive grain-surface and ice-mantle chemistry
• The earliest phases of star formation - A Herschel key project. The thermal structure of low-mass molecular cloud cores
• Characterizing young protostellar disks with the CALYPSO IRAM-PdBI survey: large Class 0 disks are rare
• Hipparcos distances of Ophiuchus and Lupus cloud complexes
• The ALMA-PILS survey: Inventory of complex organic molecules towards IRAS 16293-2422 A
• Infalling-Rotating Motion and Associated Chemical Change in the Envelope of IRAS 16293-2422 Source A Studied with ALMA
• The ALMA-PILS survey: First detections of deuterated formamide and deuterated isocyanic acid in the interstellar medium
• The Perseus ALMA Chemistry Survey (PEACHES). I. The Complex Organic Molecules in Perseus Embedded Protostars
• Decoupling of Magnetic Fields in Collapsing Protostellar Envelopes and Disk Formation and Fragmentation
• The ALMA-PILS survey: Complex nitriles towards IRAS 16293--2422
• ALMA chemical survey of disk-outflow sources in Taurus (ALMA-DOT) VI: Accretion shocks in the disk of DG Tau and HL Tau
• Complex organic molecules in low-mass protostars on solar system scales -- I. Oxygen-bearing species
• Chemical differentiation in a prestellar core traces non-uniform illumination
• Complex organics in IRAS 4A revisited with ALMA and PdBI: Striking contrast between two neighbouring protostellar cores
• L483: Warm Carbon-Chain Chemistry Source Harboring Hot Corino Activity
• Discovery of a Hot Corino in the Bok Globule B335
• Disk and Envelope Structure in Class 0 Protostars: II. High Resolution Millimeter Mapping of the Serpens Sample
• Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE
• Detection of Infall in the Protostar B335 with ALMA
• A Substellar-Mass Protostar and its Outflow of IRAS 15398-3359 Revealed by Subarcsecond-Resolution Observations of H${}_2$CO and CCH
• Formation and Evolution of Disks around Young Stellar Objects
• Infall and Outflow around the HH 212 protostellar system
• The Herschel-PACS legacy of low-mass protostars: Properties of warm and hot gas and its origin in far-UV illuminated shocks
• First Abundance Measurement of Organic Molecules in the Atmosphere of HH 212 Protostellar Disk
• Looking into the hearts of Bok globules: MM and submm continuum images of isolated star-forming cores
• Complex organic molecules in low-mass protostars on Solar System scales -- II. Nitrogen-bearing species
• Rotation in the NGC 1333 IRAS 4C Outflow
• Subarcsecond Analysis of Infalling-Rotating Envelope around the Class I Protostar IRAS 04365+2535
• Chemical segregation toward massive hot cores: The AFGL2591 star forming region
• Chemical survey toward young stellar objects in the Perseus molecular cloud complex
• FAUST I. The hot corino at the heart of the prototypical Class I protostar L1551 IRS5
• Chemical Variation among Protostellar Cores: Dependence on Prestellar Core Conditions
• Kinematics around the B335 protostar down to au scales
• Geometric and Kinematic Structure of the Outflow/Envelope System of L1527 Revealed by Subarcsecond-resolution Observation of CS
• Chemical and Physical Picture of IRAS 16293-2422 Source B at a Sub-arcsecond Scale Studied with ALMA
• FAUST II. Discovery of a Secondary Outflow in IRAS 15398-3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?
• Constraining the Infalling Envelope Models of Embedded Protostars: BHR 71 and its Hot Corino
• Ionization: a possible explanation for the difference of mean disk sizes in star-forming regions
• Large-scale magnetic fields in Bok globules
• Sulfur-Bearing Species Tracing the Disk/Envelope System in the Class I Protostellar Source Elias 29
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars I. Identifying and Characterizing the Protostellar Content of the OMC2-FIR4 and OMC2-FIR3 Regions
• FAUST III. Misaligned rotations of the envelope, outflow, and disks in the multiple protostellar system of VLA 1623$-$2417
• Organic chemistry in the protosolar analogue HOPS-108: Environment matters
• CO in Protostars (COPS): $Herschel$-SPIRE Spectroscopy of Embedded Protostars
• A Survey of CH2DOH Towards Starless and Prestellar Cores in the Taurus Molecular Cloud
• Substructures in the Disk-Forming Region of the Class 0 Low-Mass Protostellar Source IRAS 16293-2422 Source A on a 10 au Scale
• Probing the effects of external irradiation on low-mass protostars through unbiased line surveys
• Sub-arcsecond Kinematic Structure of the Outflow in the Vicinity of the Protostar in L483
• Hot corino chemistry in the Class I binary source Ser-emb 11
• Molecular Distributions of the Disk/Envelope System of L483: Principal Component Analysis for the Image Cube Data

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• CoCCoA: Complex Chemistry in hot Cores with ALMA. Selected oxygen-bearing species
• ALMA-IMF XI: The sample of hot core candidates A rich population of young high-mass proto-stars unveiled by the emission of methyl formate
• Chemical Differentiation and Temperature Distribution on a Few au Scale around the Protostellar Source B335
• 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
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Parsec scales of carbon chain and complex organic molecules in AFGL 2591 and IRAS 20126