Dynamics of cluster-forming hub-filament systems

• Verfasst von: Treviño Morales, Sandra [VerfasserIn]
• Verfasst von: Geen, Samuel Thomas [VerfasserIn]
• Titel: Dynamics of cluster-forming hub-filament systems
• Titelzusatz: the case of the high-mass star-forming complex Monoceros R2
• Verf.angabe: S.P. Treviño-Morales, A. Fuente, Á Sánchez-Monge, J. Kainulainen, P. Didelon, S. Suri, N. Schneider, J. Ballesteros-Paredes, Y.-N. Lee, P. Hennebelle, P. Pilleri, M. González-García, C. Kramer, S. García-Burillo, A. Luna, J.R. Goicoechea, P. Tremblin, S. Geen
• E-Jahr: 2019
• Jahr: 12 September 2019
• Umfang: 44 S.
• Fussnoten: Gesehen am 02.10.2019
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Ort Quelle: Les Ulis : EDP Sciences, 1969
• Jahr Quelle: 2019
• Band/Heft Quelle: 629(2019) Artikel-Nummer A81, 44 Seiten
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/201935260
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1678052361

Abstract

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 13CO and C18O 1 →0 and 2 →1 lines obtained with the IRAM-30 m telescope. We also used H2 column density maps derived from Herschel dust emission observations. Results: We identified the filamentary network in Mon R2 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⊙ pc−1 and show signs of fragmentation, while the secondary filaments have line masses of 12-60 M⊙ 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⊙ yr−1 into the central hub. The secondary filaments accrete into the main filaments at a rate of 0.1-0.4 × 10−4 M⊙ 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 ~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.