Evolution of spatio-kinematic structures in star-forming regions: are Friends of Friends worth knowing?

Parker, R. J.; Wright, N. J.

doi:10.1093/mnras/sty2372

Cited by 8 publications

(6 citation statements)

References 60 publications

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“…When we do this simplistic tallying, we find that the simulations most consistent with the observations are those that start with compact (r F = 1 pc) and substructured (D = 1.6) initial conditions, which are very dense (10 4 M ⊙ pc −3 ). The initial bulk motion can either be subvirial (α vir = 0.3) or in virial equilibrium (α vir = 0.5); in fact, this is a weak constraint because the local velocity dispersions in the substructure are usually highly subvirial (Parker & Wright 2016;Parker & Wright 2018). These compact, highly substructured initial conditions are also the optimal initial conditions identified from the RW/WW analysis in Schoettler et al (2021).…”

Section: N-body Simulationsmentioning

confidence: 99%

Constraints on star formation in NGC 2264

Parker

Schoettler

2021

Monthly Notices of the Royal Astronomical Society

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We quantify the spatial distribution of stars for two subclusters centred around the massive/intermediate mass stars S Mon and IRS 1/2 in the NGC 2264 star-forming region. We find that both subclusters are have neither a substructured, nor a centrally concentrated distribution according to the $\mathcal {Q}$-parameter. Neither subcluster displays mass segregation according to the ΛMSR ratio, but the most massive stars in IRS 1/2 have higher relative surface densities according to the ΣLDR ratio. We then compare these quantities to the results of N-body simulations to constrain the initial conditions of NGC 2264, which are consistent with having been dense ($\tilde{\rho } \sim 10^4$ M⊙ pc−3), highly substructured and subvirial. These initial conditions were also derived from a separate analysis of the runaway and walkaway stars in the region, and indicate that star-forming regions within 1 kpc of the Sun likely have a broad range of initial stellar densities. In the case of NGC 2264, its initial stellar density could have been high enough to cause the destruction or truncation of protoplanetary discs and fledgling planetary systems due to dynamical encounters between stars in the early stages of its evolution.

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Section: N-body Simulationsmentioning

confidence: 99%

Constraints on star formation in NGC 2264

Parker

Schoettler

2021

Monthly Notices of the Royal Astronomical Society

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“…Spatial analyses of observations and simulations have been applied to density and radius estimation, membership, and multiplicity determination, as well as mass segregation (see e.g., Casertano & Hut 1985;Gomez et al 1993;Larson 1995;Maíz-Apellániz et al 2004;Cartwright & Whitworth 2004;Allison et al 2009;Parker & Goodwin 2015;Maschberger & Clarke 2011;Buckner et al 2019). In recent years, analyses have been extended to the spatio-kinematical phase space, allowing us to estimate the kinematical state of clusters and associations, generate catalogues, or distinguish between different populations within the Milky Way (see e.g., Fűrész et al 2006;Parker et al 2014;Wright et al 2014;Alfaro & González 2016;Parker & Wright 2018;Cantat-Gaudin et al 2018).…”

Section: Introductionmentioning

confidence: 99%

S2D2: Small-scale Significant substructure DBSCAN Detection

González

Joncour

Buckner

et al. 2021

A&A

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Context. The spatial and dynamical structure of star-forming regions can offer insights into stellar formation patterns. The amount of data from current and upcoming surveys calls for robust and objective procedures for detecting structures in order to statistically analyse the various regions and compare them. Aims. We aim to provide the community with a tool capable of detecting, above random expectations, the small-scale significant structure in star-forming regions that could serve as an imprint of the stellar formation process. The tool makes use of the one-point correlation function to determine an appropriate length scale for ϵ and uses nearest-neighbour statistics to determine a minimum number of points Nmin for the DBSCAN algorithm in the neighbourhood of ϵ. Methods. We implemented the procedure and applied it to synthetic star-forming regions of different nature and characteristics to obtain its applicability range. We also applied the method to observed star-forming regions to demonstrate its performance in realistic circumstances and to analyse its results. Results. The procedure successfully detects significant small-scale substructures in heterogeneous regions, fulfilling the goals it was designed for and providing very reliable structures. The analysis of regions close to complete spatial randomness (Q ∈ [0.7, 0.87]) shows that even when some structure is present and recovered, it is hardly distinguishable from spurious detection in homogeneous regions due to projection effects. Thus, any interpretation should be done with care. For concentrated regions, we detect a main structure surrounded by smaller ones, corresponding to the core plus some Poisson fluctuations around it. We argue that these structures do not correspond to the small compact regions we are looking for. In some realistic cases, a more complete hierarchical, multi-scale analysis would be needed to capture the complexity of the region. Conclusions. We carried out implementations of our procedure and devised a catalogue of the Nested Elementary STructures (NESTs) detected as a result in four star-forming regions (Taurus, IC 348, Upper Scorpius, and Carina). This catalogue is being made publicly available to the community. Implementations of the 3D versionsof the procedure, as well as up to 6D versions, including proper movements, are in progress and will be provided in a future work.

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Section: N-body Simulationsmentioning

confidence: 99%

Constraints on star formation in NGC2264

Parker,

Schoettler

2021

Preprint

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We quantify the spatial distribution of stars for two subclusters centred around the massive/intermediate mass stars S Mon and IRS 1/2 in the NGC 2264 star-forming region. We find that both subclusters are have neither a substructured, nor a centrally concentrated distribution according to the Q-parameter. Neither subcluster displays mass segregation according to the Λ MSR ratio, but the most massive stars in IRS 1/2 have higher relative surface densities according to the Σ LDR ratio. We then compare these quantities to the results of N-body simulations to constrain the initial conditions of NGC 2264, which are consistent with having been dense ( ρ ∼ 10 4 M ⊙ pc −3 ), highly substructured and subvirial. These initial conditions were also derived from a separate analysis of the runaway and walkaway stars in the region, and indicate that starforming regions within 1 kpc of the Sun likely have a broad range of initial stellar densities. In the case of NGC 2264, its initial stellar density could have been high enough to cause the destruction or truncation of protoplanetary discs and fledgling planetary systems due to dynamical encounters between stars in the early stages of its evolution.

show abstract

Evolution of spatio-kinematic structures in star-forming regions: are Friends of Friends worth knowing?

Cited by 8 publications

References 60 publications

Constraints on star formation in NGC 2264

Constraints on star formation in NGC 2264

S2D2: Small-scale Significant substructure DBSCAN Detection

Constraints on star formation in NGC2264

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