Observational Characteristics of the First Protostellar Cores

Abstract

First protostellar cores are young stellar objects in the earliest evolutionary stage. They are hydrostatic objects formed soon after the central portions of star-forming cores become optically thick to dust emission. We consider their characteristics in the emitted radiation, and discuss their evolution with increasing mass of the cores. Particular attention is paid to detailed radiative and chemical processes in the postshock relaxation layer located at the surface of the core, where the majority of radiation is emitted. Most of the radiation is originally emitted in the dust continuum in mid-infrared wavelength (~10-30 micron), which reprocessed to far-infrared with ~100-200 micron. Although some fraction (~0.1) of the radiation energy is emitted in the H2O lines at the accretion shock, most is absorbed and reemitted in the dust continuum in the envelope. The H2O lines account for at most ~1/100 of the observed luminosity. If a cavity is present in the envelope due to outflow or rotation, the dust and H2O line emission in the mid-infrared wavelength from the shock can be observed directly, or as a reflection nebula. Among forthcoming observational facillities, SPICA is the most suitable for detecting either direct or processed radiation from first-core objects.

To appear in PASJ vol.59

References in corpus (6)

• An atomic and molecular database for analysis of submillimetre line observations
• Thermal and Fragmentation Properties of Star-forming Clouds in Low-metallicity Environments
• Evolution of Chemistry and Molecular Line Profile during Protostellar Collapse
• The Spitzer c2d Survey of Nearby Dense Cores: II: Discovery of a Low Luminosity Object in the "Evolved Starless Core" L1521F
• Evolutionary Signatures in the Formation of Low-Mass Protostars
• The evolutionary state of the southern dense core Cha-MMS1

Cited by in corpus (30)

• Star Formation in the Milky Way and Nearby Galaxies
• Molecular Evolution and Star Formation: From Prestellar Cores to Protostellar Cores
• Herschel observations of B1-bS and B1-bN: two first hydrostatic core candidates in the Perseus star-forming cloud
• Nitrogen isotopic ratios in Barnard 1: a consistent study of the N2H+, NH3, CN, HCN and HNC isotopologues
• A Candidate Detection of the First Hydrostatic Core
• IC348-SMM2E: a Class 0 proto-brown dwarf candidate forming as a scaled-down version of low-mass stars
• Detection of a Bipolar Molecular Outflow Driven by a Candidate First Hydrostatic Core
• Nonlinear Evolution of Global Hydrodynamic Shallow-Water Instability in Solar Tachocline
• Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores. I. Spectral energy distributions and evolutionary sequence
• Physical and radiative properties of the first core accretion shock
• Two Extreme Young Objects in Barnard 1-b
• How Starless Are Starless Cores?
• Synthetic observations of star formation and the interstellar medium
• Chemistry in the First Hydrostatic Core Stage By Adopting Three-Dimensional Radiation Hydrodynamic Simulations
• The dynamical state of the First Hydrostatic Core Candidate Cha-MMS1
• ALMA detections of the youngest protostars in Ophiuchus
• Organic chemistry of low-mass star-forming cores I: 7 mm spectroscopy of Chamaeleon MMS1
• Probing the Earliest Stage of Protostellar Evolution -- Barnard 1-bN and Barnard 1-bS
• Initial conditions for star formation in clusters: physical and kinematical structure of the starless core Oph A-N6
• Conditions for HD Cooling in the First Galaxies Revisited: Interplay between Far-Ultraviolet and Cosmic Ray Feedback in Population III Star Formation
• The Earliest Phases of Star formation (EPoS): Temperature, density, and kinematic structure of the star-forming core CB 17
• The nature of very low luminosity objects (VeLLOs)
• Protostellar-disc fragmentation across all metallicities
• Seeds of Life in Space (SOLIS).VII. Discovery of a cold dense methanol blob toward the L1521F VeLLO system
• ALMA Observations of SMM11 Reveal an Extremely Young Protostar in Serpens Main Cluster
• What can the SEDs of first hydrostatic core candidates reveal about their nature?
• Emission from a Young Protostellar Object I. Signatures of Young Embedded Outflows
• A 1000 AU Scale Molecular Outflow Driven by a Protostar with an age of <4000 Years
• Insights into the first and second hydrostatic core stages from numerical simulations
• Cooling of young stars growing by disk accretion