Mother of dragons: A massive, quiescent core in the dragon cloud (IRDC G028.37+00.07)
Artikel i vetenskaplig tidskrift, 2023
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 clouda'(also known as G028.37+00.07 or Cloud Ca). 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 ( 3s ∼ 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.
ISM: structure
ISM: clouds
Stars: formation
Stars: massive
Författare
Ashley T. Barnes
Universität Bonn
European Southern Observatory (ESO)
Junhao Liu
East Asian Observatory
Q. Zhang
Harvard-Smithsonian Center for Astrophysics
Jonathan Tan
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
University of Virginia
F. Bigiell
Universität Bonn
P. Caselli
Max-Planck-Gesellschaft
Giuliana Cosentino
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Francesco Fontani
Osservatorio Astrofisico di Arcetri
Jonathan D. Henshaw
Liverpool John Moores University
Max-Planck-Gesellschaft
I. Jimenez-Serra
Instituto Nacional de Tecnica Aeroespacial
D. S. Kalb
Max-Planck-Gesellschaft
Chi Yan Law
European Southern Observatory (ESO)
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
S. Longmore
Liverpool John Moores University
R. J. Parker
University of Sheffield
J. Pineda
Max-Planck-Gesellschaft
A. Sanchez-Monge
Observatorio Astronómico Nacional (OAN)
Wanggi Lim
California Institute of Technology (Caltech)
Ke Wang
Beijing University of Technology
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 675 A53Ämneskategorier
Astronomi, astrofysik och kosmologi
Atom- och molekylfysik och optik
Annan fysik
Sannolikhetsteori och statistik
DOI
10.1051/0004-6361/202245668