Warm Extended Dense Gas Lurking At The Heart Of A Cold Collapsing Dense Core

Abstract

In order to investigate when and how the birth of a protostellar core occurs, we made survey observations of four well-studied dense cores in the Taurus molecular cloud using CO transitions in submillimeter bands. We report here the detection of unexpectedly warm (~ 30 - 70 K), extended (radius of ~ 2400 AU), dense (a few times 10^{5} cm^{-3}) gas at the heart of one of the dense cores, L1521F (MC27), within the cold dynamically collapsing components. We argue that the detected warm, extended, dense gas may originate from shock regions caused by collisions between the dynamically collapsing components and outflowing/rotating components within the dense core. We propose a new stage of star formation, "warm-in-cold core stage (WICCS)", i.e., the cold collapsing envelope encases the warm extended dense gas at the center due to the formation of a protostellar core. WICCS would constitutes a missing link in evolution between a cold quiescent starless core and a young protostar in class 0 stage that has a large-scale bipolar outflow.

Accepted for publication in The Astrophysical Journal Letters

References in corpus (5)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores
• The Initial Conditions for Gravitational Collapse of a Core: An Extremely Young Low-Mass Class 0 Protostar GF9-2
• Submillimeter Observations of The Isolated Massive Dense Clump IRAS 20126+4104
• Spectroscopic Evidence for Gas Infall in GF9-2

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• Kinematics and Physical Conditions of the Innermost Envelope in B335
• Direct Imaging of a Compact Molecular Outflow from a Very Low-luminosity Object; L1521F-IRS
• Warm CO gas generated by possible turbulent shocks in a low-mass star-forming dense core in Taurus
• The dynamical state of the First Hydrostatic Core Candidate Cha-MMS1
• AMI Large Array radio continuum observations of Spitzer c2d small clouds and cores
• Seeds of Life in Space (SOLIS).VII. Discovery of a cold dense methanol blob toward the L1521F VeLLO system
• Twisted magnetic field in star formation processes of L1521 F revealed by submillimeter dual band polarimetry using James Clerk Maxwell Telescope
• ALMA Band 9 CO(6--5) Reveals a Warm Ring Structure Associated with the Embedded Protostar in the Cold Dense Core MC 27/L1521F
• Galaxies as fluctuations in cosmic stellar liquid