Modeling the Physical Structure of the Low Density Pre-protostellar Core Lynds 1498

Abstract

Lynds 1498 is a pre-protostellar core (PPC) and was one of the initial objects toward which molecular depletion and differentiation was detected. Despite the considerable scrutiny of L1498, there has not been a extensive study of the density and temperature structure as derived from radiative transfer modeling of dust continuum observations. We present deep SCUBA observations of L1498 at 850 and 450 micron, high resolution BEARS maps of the N2H+ 1-0 transition, CSO observations of the N2H+ 3-2 transition, and GBT observations of the C3S 4-3 transition. We also present a comparison of derived properties between L1498 and nearby PPCs that have been observed at far-infrared and submillimeter wavelengths. We present a more realistic treatment of PPC heating which varies the strength of the ISRF, Sisrf, and includes attenuation of the ISRF due to dust grains at the outer radius of the core, Av. The best-fitted model consists of a Bonner-Ebert sphere with a central density of 1 - 3 x 10^4 cm-3, R_o ~ 0.29 pc, 0.5 <= Sisrf <= 1, Av ~ 1 mag, and a nearly isothermal temperature profile of ~ 10.5 K for OH8 opacities. C3S emission shows a central depletion hole while N2H+ emission is centrally peaked. The observed depletions of C3S and H2CO, the modest N2H+ abundance, and a central density that is an order of magnitude lower than other modeled PPCs suggests that L1498 may be a forming PPC. Our derived temperature and density profile will improve modeling of molecular line observations that will explicate the core's kinematical and chemical state. (abridged)

26 pages, 10 figures (2 color figs). Accepted to ApJ

References in corpus (30)

• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Physical Conditions in Regions of Star Formation
• Systematic Molecular Differentiation in Starless Cores
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Molecular ions in L1544. II. The ionization degree
• Tracing the Mass during Low-Mass Star Formation. II. Modelling the Submillimeter Emission from Pre-Protostellar Cores
• Physical structure and CO abundance of low-mass protostellar envelopes
• The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling
• Tracing the Mass during Low-Mass Star Formation. I. Submillimeter Continuum Observations
• Evolution of Chemistry and Molecular Line Profile during Protostellar Collapse
• Tracing the Mass during Low-Mass Star Formation. III. Models of the Submillimeter Dust Continuum Emission from Class 0 Protostars
• The dust temperature distribution in prestellar cores
• The initial conditions of isolated star formation. V: ISOPHOT imaging and the temperature and energy balance of pre-stellar cores
• Tracing the Mass during Low-Mass Star Formation, IV: Observations and Modeling of the Submillimeter Continuum Emission from Class I Protostars
• Molecular Evolution in Collapsing Prestellar Cores II: The Effect of Grain-surface Reactions
• Probing Pre-Protosellar Cores with Formaldehyde
• Multi-epoch VLBA observations of T Tauri South
• Dust emissivity in the Submm/Mm: SCUBA and SIMBA observations of Barnard 68
• Freeze-out and coagulation in pre-protostellar collapse
• L1521E: the first starless core with no molecular depletion
• Radiative Transfer and Starless Cores
• On the atmospheric limitations of ground-based submillimetre astronomy using array receivers
• L1521E: A Starless Core in the Early Evolutionary Stage ?
• A Coupled Dynamical and Chemical Model of Starless Cores of Magnetized Molecular Clouds: I. Formulation and Initial Results
• N2H+ Observations of Molecular Cloud Cores in Taurus
• Molecular Line Observations of Carbon-Chain-Producing Regions L1495B and L1521B
• The Physical and Chemical Status of Pre-protostellar Core B68
• Monte Carlo radiative transfer in molecular cloud cores
• Discovery of a Dusty Ring in the Coalsack: A Dense Core Caught in the Act of Formation?

Cited by in corpus (73)

• How to Calculate Molecular Column Density
• On the internal structure of starless cores. II. A molecular survey of L1498 and L1517B
• Resolving the Luminosity Problem in Low-Mass Star Formation
• Evolutionary Signatures in the Formation of Low-Mass Protostars. II. Towards Reconciling Models and Observations
• The earliest phases of star formation - A Herschel key project. The thermal structure of low-mass molecular cloud cores
• The Spitzer c2d Survey of Nearby Dense Cores: II: Discovery of a Low Luminosity Object in the "Evolved Starless Core" L1521F
• Dynamics of Dense Cores in the Perseus Molecular Cloud
• The Spitzer c2d Survey of Nearby Dense Cores: I: First Direct Detection of the Embedded Source in IRAM 04191+1522
• CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud
• The Bolocam Galactic Plane Survey. XIV. Physical Properties of Massive Starless and Star Forming Clumps
• Filamentary Accretion Flows in the Infrared Dark Cloud G14.225-0.506 Revealed by ALMA
• Observational Constraints on Submillimeter Dust Opacity
• The Envelope and Embedded Disk around the Class 0 Protostar L1157-mm: Dual-wavelength Interferometric Observations and Modeling
• The Dust Emissivity Spectral Index in the Starless Core TMC-1C
• Prevalence of Complex Organic Molecules in Starless and Prestellar Cores within the Taurus Molecular Cloud
• A Search for Carbon-Chain-Rich Cores in Dark Clouds
• Detection of a Bipolar Molecular Outflow Driven by a Candidate First Hydrostatic Core
• Nonlinear Evolution of Global Hydrodynamic Shallow-Water Instability in Solar Tachocline
• ALMA observations of fragmentation, sub-structure, and protostars in high-mass starless clump candidates
• CCH in prestellar cores
• An ALMA Search for Substructure, Fragmentation, and Hidden Protostars in Starless Cores in Chamaeleon I
• The Spitzer c2d Survey of Nearby Dense Cores. V. Discovery of a VeLLO in the "Starless" Dense Core L328
• Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. I. Varied Shock Speeds
• The effect of a strong external radiation field on protostellar envelopes in Orion
• An Observed Lack of Substructure in Starless Cores
• The Spitzer c2d Survey of Nearby Dense Cores. IX. Discovery of a Very Low Luminosity Object Driving a Molecular Outflow in the Dense Core L673-7
• Evidence for Large Grains in the Star-forming Filament OMC-2/3
• Spitzer and HHT observations of starless cores: masses and environments
• Laboratory evidence for the non-detection of excited nascent H2 in dark clouds
• The JCMT Gould Belt Survey: Evidence for Dust Grain Evolution in Perseus Star-forming Clumps
• Probing the Protostellar Envelope around L1157: the Dust and Gas Connection
• Grain size limits derived from 3.6 μm and 4.5 μm coreshine
• Density profile evolution during prestellar core collapse: Collapse starts at the large scale
• Molecular Line Observations of a Carbon-Chain-Rich Core L492
• The JCMT and Herschel Gould Belt Surveys: A comparison of SCUBA-2 and Herschel data of dense cores in the Taurus dark cloud L1495
• A (sub)millimetre study of dense cores in Orion B9
• Detection of Complex Organic Molecules in Young Starless Core L1521E
• CB17: Inferring the dynamical history of a prestellar core with chemo-dynamical models
• Herschel and SCUBA-2 observations of dust emission in a sample of Planck cold clumps
• A Survey of CH2DOH Towards Starless and Prestellar Cores in the Taurus Molecular Cloud
• C18O Depletion in Starless Cores in Taurus
• MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars
• Molecular Cloud Cores with High Deuterium Fraction: Nobeyama Single-Pointing Survey
• Earliest phases of star formation (EPoS): Dust temperature distributions in isolated starless cores
• The JCMT Gould Belt Survey: the effect of molecular contamination in SCUBA-2 observations of Orion A
• Relationship between the column density distribution and evolutionary class of molecular clouds as viewed by ATLASGAL
• L1506: a prestellar core in the making
• Prestellar and protostellar cores in Ori B9
• Determination of the far-infrared dust opacity in a prestellar core
• Revealing The Millimeter Environment of the New FU Orionis Candidate HBC722 with the Submillimeter Array
• Observations of Cyanopolyynes toward Four High-Mass Star-Forming Regions Containing Hot Cores
• Smoke in the Pipe Nebula: dust emission and grain growth in the starless core FeSt 1-457
• Spitzer observations of a 24 micron shadow: Bok Globule CB190
• Correlating Infall with Deuterium Fractionation in Dense Cores
• ORion Alma New GEneration Survey (ORANGES) I. Dust continuum and free-free emission of OMC-2/3 filament protostars
• Interferometric Observations of Cyanopolyynes toward the G28.28-0.36 High-Mass Star-Forming Region
• Physical and Chemical Structure of the Disk and Envelope of the Class 0/I Protostar L1527
• The JCMT BISTRO Survey: Studying the Complex Magnetic Field of L43
• Molecular Cloud Cores with High Deuterium Fractions: Nobeyama Mapping Survey
• Herschel dust emission as a probe of starless cores mass: MCLD 123.5+24.9 of the Polaris Flare
• 3D Radiative Transfer Modelling and Virial Analysis of Starless Cores in the B10 Region of the Taurus Molecular Cloud
• The Role of Non-ionizing Radiation Pressure in Star Formation: The Stability of Cores and Filaments
• SMA observations of C2H in High-Mass Star Forming Regions
• On the internal dynamics of starless cores: stability of starless cores with internal motions and collapse dynamics
• Cold Dust in Hot Regions
• A Survey of Deuterated Ammonia in the Cepheus Star-Forming Region L1251
• Nobeyama Survey of Inward Motions toward Cores in Orion Identified by SCUBA-2
• An ALMA search for substructure and fragmentation in starless cores in Orion B North
• Mass estimates for very cold (< 8 K) gas in molecular cloud cores
• Erosion of a dense molecular core by a strong outflow from a massive protostar
• The Power of SOFIA/FORCAST in Estimating Internal Luminosities of Low Mass Class 0/I Protostars
• Deuterium fractionation of the starless core L 1498
• Limitations of the modified blackbody fit method for determining molecular cloud properties