G11.92-0.61-MM2: A Bonafide Massive Prestellar Core?

Abstract

Core accretion models of massive star formation require the existence of stable massive starless cores, but robust observational examples of such objects have proven elusive. We report subarcsecond-resolution SMA 1.3 mm, 1.1 mm, and 0.88 mm and VLA 1.3 cm observations of an excellent massive starless core candidate, G11.92-0.61-MM2, initially identified in the course of studies of GLIMPSE Extended Green Objects (EGOs). Separated by ~7.2" from the nearby MM1 protostellar hot core, MM2 is a strong, compact dust continuum source (submillimeter spectral index alpha=2.6+/-0.1), but is devoid of star formation indicators. In contrast to MM1, MM2 has no masers, no centimeter continuum, and no (sub)millimeter wavelength line emission in ~24 GHz of bandwidth observed with the SMA, including N2H+(3-2), HCO+(3-2), and HCN(3-2). Additionally, there is no evidence for an outflow driven by MM2. The (sub)millimeter spectral energy distribution (SED) of MM2 is best fit with a dust temperature of ~17-19 K and luminosity of ~5-7 L_sun. The combined physical properties of MM2, as inferred from its dust continuum emission, are extreme: M>30 M_sun within a radius<1000 AU, N(H2)>10^25 cm^-2 and n(H2)>10^9 cm^-3. Comparison of the molecular abundance limits derived from our SMA observations with gas-grain chemical models indicates that extremely dense (n(H)>>10^8 cm^-3), cold (<20 K) conditions are required to explain the lack of observed (sub)millimeter line emission, consistent with the dust continuum results. Our data suggest that G11.92-0.61-MM2 is the best candidate for a bonafide massive prestellar core found to date, and a promising target for future, higher-sensitivity observations.

arXiv commentApJ Letters, accepted. 19 pages including 3 figures and 2 tables

References in corpus (32)

• A computer program for fast non-LTE analysis of interstellar line spectra
• The Formation of Massive Stars from Turbulent Cores
• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Rosseland and Planck Mean Opacities for Protoplanetary Discs
• The mass function of dense molecular cores and the origin of the IMF
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Cosmic-ray ionization of molecular clouds
• Massive star formation in 100,000 years from turbulent and pressurized molecular clouds
• Low Virial Parameters in Molecular Clouds: Implications for High Mass Star Formation and Magnetic Fields
• Reactive Desorption and Radiative Association as Possible Drivers of Complex Molecule Formation in the Cold Interstellar Medium
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Fragmentation and mass segregation in the massive dense cores of Cygnus X
• The Simultaneous Formation of Massive Stars and Stellar Clusters
• The Fragmentation of Magnetized, Massive Star-Forming Cores with Radiative Feedback
• The Dynamics of Massive Starless Cores with ALMA
• Extragalactic millimeter-wave point source catalog, number counts and statistics from 771 square degrees of the SPT-SZ Survey
• CO outflows from high-mass Class 0 protostars in Cygnus-X
• Cosmic-ray ionisation in collapsing clouds
• Modeling the Resolved Disk Around the Class 0 Protostar L1527
• Chemistry in Protoplanetary Disks: A Sensitivity Analysis
• Trigonometric Parallaxes of Star Forming Regions in the Scutum Spiral Arm
• A Unified Monte Carlo Treatment of Gas-Grain Chemistry for Large Reaction Networks. I. Testing Validity of Rate Equations in Molecular Clouds
• Bipolar Molecular Outflows and Hot Cores in GLIMPSE Extended Green Objects (EGOs)
• Dense cores in the Pipe Nebula: An improved core mass function
• Subarcsecond Imaging of the NGC 6334 I(N) Protocluster: Two Dozen Compact Sources and a Massive Disk Candidate
• A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
• Deep Very Large Array Radio Continuum Surveys of GLIMPSE Extended Green Objects (EGOs)
• Constraining the properties of 1.2-mm dust clumps that contain luminous water masers
• First Results from a 1.3 cm EVLA Survey of Massive Protostellar Objects: G35.03+0.35
• The Protocluster G18.67+0.03: A Test Case for Class I Methanol Masers as Evolutionary Indicators for Massive Star Formation
• Observational studies of pre-stellar cores and infrared dark clouds

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• G11.92-0.61 MM1: A Keplerian disc around a massive young proto-O star
• 'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016
• Distributed star formation throughout the Galactic Center cloud Sgr B2
• Infall Signatures in a Prestellar Core embedded in the High-Mass 70 $\mu$m Dark IRDC G331.372-00.116
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XV. Steady Accretion from Global Collapse to Core Feeding in Massive Hub-filament System SDC335
• Unveiling the Early-Stage Anatomy of a Protocluster Hub with ALMA
• Simultaneous low- and high-mass star formation in a massive protocluster: ALMA observations of G11.92-0.61
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• The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
• The ATLASGAL survey: The sample of young massive cluster progenitors
• An ALMA study of hub-filament systems I. On the clump mass concentration within the most massive cores
• Surveys of Clumps, Cores, and Condensations in Cygnus X: I. a New Catalog of ~0.1 pc Massive Dense Cores
• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). IV. Star formation signatures in G023.477
• High-mass Starless Clumps in the inner Galactic Plane: the Sample and Dust Properties
• HII regions and high-mass starless clump candidates II. Fragmentation and induced star formation at ~0.025 pc scale: An ALMA continuum study
• Identification of prestellar cores in high-mass star forming clumps via ${\mathrm{H}}_2{\mathrm{D}}^{+}$ observations with ALMA
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• Molecular analysis of a high-mass prestellar core candidate in W43-MM1
• Mother of Dragons: A Massive, quiescent core in the dragon cloud (IRDC G028.37+00.07)
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• Lack of high-mass prestellar cores in the starless MDCs of NGC6334
• Fragmentation and kinematics in high-mass star formation: CORE-extension targeting two very young high-mass star-forming regions
• VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers
• High-Mass Star Formation
• Discovery of a 500 au Protobinary in the Massive Prestellar Core G11.92-0.61 MM2
• ALMA-IMF XVII -- Census and lifetime of high-mass prestellar cores in 14 massive protoclusters
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• SOFIA {\it FORCAST} Photometry of 12 Extended Green Objects in the Milky Way
• Multiple outflows in the high-mass cluster forming region, G25.82-0.17
• Comparison of Low-Mass and High-Mass Star Formation
• Dense cores in the Seahorse infrared dark cloud: physical properties from modified blackbody fits to the far-infrared-submillimetre spectral energy distributions
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