Dynamics of cluster-forming hub-filament systems The case of the high-mass star-forming complex Monoceros R2
Journal article, 2019

Context. High-mass stars and star clusters commonly form within hub-filament systems. Monoceros R2 (hereafter Mon R2), at a distance of 830 pc, harbors one of the closest of these systems, making it an excellent target for case studies. Aims. We investigate the morphology, stability and dynamical properties of the Mon R2 hub-filament system. Methods. We employed observations of the (CO)-C-13 and (CO)-O-18 1 -> 0 and 2 -> 1 lines obtained with the IRAM-30m telescope. We also used H-2 column density maps derived from Herschel dust emission observations. Results. We identified the filamentary network in Mon R-2 with the DisPerSE algorithm and characterized the individual filaments as either main (converging into the hub) or secondary (converging to a main filament). The main filaments have line masses of 30-100 M-circle dot pc(-1) and show signs of fragmentation, while the secondary filaments have line masses of 12-60 M-circle dot pc(-1) and show fragmentation only sporadically. In the context of Ostriker's hydrostatic filament model, the main filaments are thermally supercritical. If non-thermal motions are included, most of them are transcritical. Most of the secondary filaments are roughly transcritical regardless of whether non-thermal motions are included or not. From the morphology and kinematics of the main filaments, we estimate a mass accretion rate of 10(-4)-10(-3) M-circle dot yr(-1) into the central hub. The secondary filaments accrete into the main filaments at a rate of 0.1-0.4 x 10(-4) M-circle dot yr(-1). The main filaments extend into the central hub. Their velocity gradients increase toward the hub, suggesting acceleration of the gas. We estimate that with the observed infall velocity, the mass-doubling time of the hub is similar to 2.5 Myr, ten times longer than the free-fall time, suggesting a dynamically old region. These timescales are comparable with the chemical age of the HII region. Inside the hub, the main filaments show a ring-or a spiral-like morphology that exhibits rotation and infall motions. One possible explanation for the morphology is that gas is falling into the central cluster following a spiral-like pattern.

ISM: kinematics and dynamics

ISM: clouds

ISM: individual objects: Monoceros R2

ISM: structure


Sandra Treviño Morales

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

A. Fuente

Spanish National Observatory (OAN)

A. Sanchez-Monge

University of Cologne

Jouni Kainulainen

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

P. Didelon

Paris Diderot University

S. Suri

Max Planck Society

University of Cologne

N. Schneider

University of Cologne

J. Ballesteros-Paredes

Universidad Nacional Autónoma de México

Y. -N. Lee

Paris Diderot University

P. Hennebelle

Paris Diderot University

P. Pilleri

University of Toulouse

M. Gonzalez-Garcia

Spanish National Research Council (CSIC)

C. Kramer

Institut de Radioastronomie Millimétrique (IRAM)

S. Garcia-Burillo

Spanish National Observatory (OAN)

A. Luna

National Institute of Astrophysics, Optics and Electronics

J. R. Goicoechea

Spanish National Research Council (CSIC)

P. Tremblin

Paris Diderot University

S. Geen

Heidelberg University

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 629 A81

Subject Categories

Astronomy, Astrophysics and Cosmology


Control Engineering



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