Edge collapse and subsequent longitudinal accretion in filament S242

Yuan, Lixia; Li, Guangxing; Zhu, Meiping; Wang, Ke; Liu, Xunchuan; Kim, Kee‐Tae; Tatematsu, Ken’ichi; Yuan, Jinghua; Wu, Yuefang

doi:10.1051/0004-6361/201936625

“…Elongated filamentary structures produced by gravitational collapse tend to accumulate mass near their ends by means of the so-called edge collapse. Yuan et al (2020) found that the structure of the 25-pc long filament S228 matches the edge collapse predictions. This mechanism can create two adjacent star clusters or groups of stars of comparable masses.…”

Section: Sequential Disk Instability (Di+di)supporting

confidence: 52%

Architecture of Hierarchical Stellar Systems and their Formation

Tokovinin¹

2021

Preprint

0

View full text Add to dashboard Cite

Accumulation of new data on stellar hierarchical systems and the progress in numerical simulations of their formation open the door to genetic classification of these systems, where properties of a certain group (family) of objects are tentatively related to their formation mechanisms and early evolution. A short review of the structure and statistical trends of known stellar hierarchies is given. Like binaries, they can be formed by the disk and core fragmentation events happening sequentially or simultaneously and followed by the evolution of masses and orbits driven by continuing accretion of gas and dynamical interactions between stars. Several basic formation scenarios are proposed and associated qualitatively with the architecture of real systems, although quantitative predictions for these scenarios are still pending. The general trend of increasing orbit alignment with decreasing system size points to the critical role of the accretion-driven orbit migration, which also explains the typically comparable masses of stars belonging to the same system. The architecture of some hierarchies bears imprints of chaotic dynamical interactions. Characteristic features of each family are illustrated by several real systems.

show abstract

“…Elongated filamentary structures produced by gravitational collapse tend to accumulate mass near their ends by means of the so-called edge collapse. Yuan et al [51] found that the structure of the 25-pc long filament S228 matches the edge collapse predictions. This mechanism can create two adjacent star clusters or groups of stars of comparable masses.…”

Section: Core Fragmentation and Capture (Cf+cf Di+cf)mentioning

confidence: 75%

Architecture of Hierarchical Stellar Systems and Their Formation

Tokovinin

¹

2021

View full text Add to dashboard Cite

Accumulation of new data on stellar hierarchical systems and the progress in numerical simulations of their formation open the door to genetic classification of these systems, where properties of a certain group (family) of objects are tentatively related to their formation mechanisms and early evolution. A short review of the structure and statistical trends of known stellar hierarchies is given. Like binaries, they can be formed by the disk and core fragmentation events happening sequentially or simultaneously and followed by the evolution of masses and orbits driven by continuing accretion of gas and dynamical interactions between stars. Several basic formation scenarios are proposed and associated qualitatively with the architecture of real systems, although quantitative predictions for these scenarios are still pending. The general trend of increasing orbit alignment with decreasing system size points to the critical role of the accretion-driven orbit migration, which also explains the typically comparable masses of stars belonging to the same system. The architecture of some hierarchies bears imprints of chaotic dynamical interactions. Characteristic features of each family are illustrated by several real systems.

show abstract

“…Ragan et al 2012;Dirienzo et al 2015;Wang et al 2016). They are observed to have multiple substructures and velocity components, which should considerably facilitate the mass aggre-the converging motion, the filaments could also have longitudinal collapse to generate dense clumps and cores at two ends, as shown in both theoretical (Clarke & Whitworth 2015) and observational (Dewangan et al 2019;Yuan et al 2020) works.…”

Section: Introductionmentioning

confidence: 92%

Convergent Filaments Contracting Towards an Intermediate-mass Prestellar Core

Ren,

Zhu,

Shi

et al. 2021

Preprint

View full text Add to dashboard Cite

Filamentary structures are closely associated with star-forming cores, but their detailed physical connections are still not clear.We studied the dense gas in the region of OMC-3 MMS-7 in Orion A molecular cloud using the molecular lines observed with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Submillimeter Array (SMA). The ALMA N 2 H + (1-0) emission has revealed three dense filaments intersected at the center, coincident with the central core MMS-7, which has a mass of 3.6 𝑀 . The filaments and cores are embedded in a parental clump with total mass of 29 𝑀 . The N 2 H + velocity field exhibits a noticeable increasing trend along the filaments towards the central core MMS-7 with a scale of 𝑣 − 𝑣 lsr 1.5 km s −1 over a spatial range of ∼20 arcsec (8 × 10 3 AU), corresponding to a gradient of 40 km s −1 pc −1 . This feature is most likely to indicate an infall motion towards the center. The derived infall rate (8 × 10 −5 𝑀 year −1 ) and timescale (3.6 × 10 5 years) are much lower than that in a spherical free-fall collapse and more consistent with the contraction of filament structures. The filaments also exhibit a possible fragmentation, but it does not seem to largely interrupt the gas structure or the infall motion towards the center. MMS-7 thus provides an example of filamentary infall into an individual prestellar core. The filament contraction could be less intense but more steady than the global spherical collapse, and may help generate an intermediate-or even high-mass star.

show abstract

Edge collapse and subsequent longitudinal accretion in filament S242

Cited by 30 publications

References 60 publications

Architecture of Hierarchical Stellar Systems and their Formation

Architecture of Hierarchical Stellar Systems and their Formation

Architecture of Hierarchical Stellar Systems and Their Formation

Convergent Filaments Contracting Towards an Intermediate-mass Prestellar Core

Contact Info

Product

Resources

About