The evolutionary status of dense cores in the NGC 1333 IRAS 4 region

Abstract

Protostellar evolution, following the formation of the protostar is becoming reasonably well characterized, but the evolution from a prestellar core to a protostar is not well known, although the first hydrostatic core (FHSC) must be a pivotal step. NGC 1333 IRAS 4C is a potentially very young object, that we directly compare with the nearby Class 0 IRAS 4A and IRAS 4B. Observational constraints are provided by spectral imaging from the JCMT Spectral Legacy Survey (330-373 GHz) and continuum and line observations from CARMA. We present integrated intensity and velocity maps of several species, including CO, H2CO and CH3OH. The velocity of an observed outflow, the degree of CO depletion, the deuteration of DCO+/HCO+ and gas kinetic temperatures are observational signatures that we present. We report differences between the three sources in four aspects: a) the kinetic temperature is much lower towards IRAS 4C, b) the line profiles of the detected species show strong outflow activity towards IRAS 4A and IRAS 4B but not towards IRAS 4C, c) the HCN/HNC is < 1 towards IRAS 4C, which confirms the cold nature of the source, d) the degree of CO depletion and the deuteration are the lowest towards the warmest of the sources, IRAS 4B. IRAS 4C seems to be in a different evolutionary state than the IRAS 4A and IRAS 4B sources. We can probably exclude the FHSC stage due to the relatively low Lsmm/Lbol (~6\%) and we investigate the earliest accretion phase of Class 0 stage and the transition between Class 0 to Class I. Our results do not show a consistent scenario for either case, with the major issue being the absence of outflow activity and the cold nature of IRAS 4C. The number of FHSC candidates in Perseus is ~10 times higher than current models predict, which suggests that the lifespan of these objects is greater than 1000 years, possibly due to an accretion rate lower than 4x10^-5 msun/yr.

19 pages, 18 figures, 3 tables; Accepted for publication in A&A

References in corpus (17)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• The Evolution of Outflow-Envelope Interactions in Low-Mass Protostars
• Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores
• Class 0 Protostars in the Perseus Molecular Cloud: A Correlation Between the Youngest Protostars and the Dense Gas Distribution
• The Spitzer c2d Survey of Nearby Dense Cores: I: First Direct Detection of the Embedded Source in IRAM 04191+1522
• The HNC/HCN Ratio in Star-Forming Regions
• Ethynyl (C2H) in massive star formation: Tracing the initial conditions?
• A Sub-arcsecond Survey Toward Class 0 Protostars in Perseus: Searching for Signatures of Protostellar Disks
• Exposed Long-lifetime First-core: A New Model of First Cores Based on Radiation Hydrodynamics
• The evolutionary state of the southern dense core Cha-MMS1
• Magneto-Hydrodynamics of Population III Star Formation
• SiO emission from low- and high-velocity shocks in Cygnus-X massive dense clumps
• Time-Resolved AU-Scale Jets Traced by Masers in the IRAS 4A/B Regions of NGC1333
• The JCMT Spectral Legacy Survey
• Observations of Water Masers in the NGC 1333 IRAS 4 Region

Cited by in corpus (5)

• The CALYPSO IRAM-PdBI survey of jets from Class 0 protostars. Are jets ubiquitous in young stars ?
• Successive deuteration in low-mass star-forming regions: the case of D${}_2$-methanol (CHD${}_2$OH) in IRAS 16293-2422
• Modeling snowline locations in protostars: The impact of the structure of protostellar cloud cores
• FAUST XV. A disk wind mapped by CH${}_3$OH and SiO in the inner 300 au of the NGC 1333 IRAS 4A2 protostar
• The factors that influence protostellar multiplicity I: Gas temperature, density, and mass in Perseus with Nobeyama