Barnes, A.T., Liu, J., Zhang, Q. et al. (15 more authors) (2023) Mother of dragons: a massive, quiescent core in the dragon cloud (IRDC G028.37+00.07). Astronomy & Astrophysics, 675. A53. ISSN 0004-6361
Abstract
Context. Core accretion models of massive star formation require the existence of massive, starless cores within molecular clouds. Yet, only a small number of candidates for such truly massive, monolithic cores are currently known.
Aims. Here we analyse a massive core in the well-studied infrared-dark cloud (IRDC) called the ‘dragon cloud’ (also known as G028.37+00.07 or ‘Cloud C’). This core (C2c1) sits at the end of a chain of a roughly equally spaced actively star-forming cores near the center of the IRDC.
Methods. We present new high-angular-resolution 1 mm ALMA dust continuum and molecular line observations of the massive core.
Results. The high-angular-resolution observations show that this region fragments into two cores, C2c1a and C2c1b, which retain significant background-subtracted masses of 23 M⊙ and 2 M⊙ (31 M⊙ and 6 M⊙ without background subtraction), respectively. The cores do not appear to fragment further on the scales of our highest-angular-resolution images (0.2″, 0.005 pc ~ 1000 AU). We find that these cores are very dense (nH2 > 106 cm−3) and have only trans-sonic non-thermal motions (ℳs ~ 1). Together the mass, density, and internal motions imply a virial parameter of <1, which suggests the cores are gravitationally unstable, unless supported by strong magnetic fields with strengths of ~1–10 mG. From CO line observations, we find that there is tentative evidence for a weak molecular outflow towards the lower-mass core, and yet the more massive core remains devoid of any star formation indicators.
Conclusions. We present evidence for the existence of a massive, pre-stellar core, which has implications for theories of massive star formation. This source warrants follow-up higher-angular-resolution observations to further assess its monolithic and pre-stellar nature.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Authors 2023. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | stars: formation; stars: massive; ISM: structure; ISM: clouds |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number ROYAL SOCIETY DHF\R\221014 DH150108 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 19 Sep 2023 15:32 |
Last Modified: | 19 Sep 2023 15:32 |
Published Version: | http://dx.doi.org/10.1051/0004-6361/202245668 |
Status: | Published |
Publisher: | EDP Sciences |
Refereed: | Yes |
Identification Number: | 10.1051/0004-6361/202245668 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:203443 |