Competitive accretion in embedded stellar clusters

By Ian A. Bonnell, Matthew R. Bate, C. Clarke, J. E. Pringle. 2001

455 citations recorded by the source corpus.

We investigate the physics of gas accretion in young stellar clusters. Accretion in clusters is a dynamic phenomenon as both the stars and the gas respond to the same gravitational potential. Accretion rates are highly non-uniform with stars nearer the centre of the cluster, where gas densities are higher, accreting more than others. This competitive accretion naturally results in both initial mass segregation and a spectrum of stellar masses. Accretion in gas-dominated clusters is well modelled using a tidal-lobe radius instead of the commonly used Bondi–Hoyle accretion radius. This works as both the stellar and gas velocities are under the influence of the same gravitational potential and are thus comparable. The low relative velocity which results means that Rtidal<RBH in these systems. In contrast, when the stars dominate the potential and are virialized, RBH<Rtidal and Bondi–Hoyle accretion is a better fit to the accretion rates.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c40c4148314c43eab51e322b2fa5c50487e1cece

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Citations in the corpus

The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X (2007, background): “High-mass stars are known to form in dense cores within molecular cloud complexes, by accretion (Yorke & Sonnhalter 2002; Krumholz et al. 2007) and/or coalescence (e.g. Bonnell et al. 2001).”
Star formation through gravitational collapse and competitive accretion (2006, methodology): “Unfortunately, Krumholz et al.̃(2005a) use globally averaged estimates for the gas density and the velocity instead of the local variables as used in the Bonnell et al.(2001a, 2004) numerical simulations.”
LIMITING ACCRETION ONTO MASSIVE STARS BY FRAGMENTATION-INDUCED STARVATION (2010, background): “Competitive Accretion A second model for the origin of the IMF, called competitive accretion, focuses on the interaction between protostars, and between a protostellar population and the gas cloud around it (Bonnell et al. 2001a,b; Bonnell & Bate 2002; Bate & Bonnell 2005).”
The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus (2008, background): “If, on the other hand, stellar masses are determined by competitive accretion (Bonnell et al. 2001), or by the protostars Note.”
RADIATION-HYDRODYNAMIC SIMULATIONS OF THE FORMATION OF ORION-LIKE STAR CLUSTERS. II. THE INITIAL MASS FUNCTION FROM WINDS, TURBULENCE, AND RADIATION (2012, background): “…Physics, University of California, Berkeley, Berkeley, CA 94720 Padoan & Nordlund 2002; Hennebelle & Chabrier 2008) or competitive accretion (e.g. Bonnell et al. 2001a,b), can predict a shape for the IMF, but in order to determine a characteristic scale must either appeal to additional physics…”
Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey (2012, background): “…mainly by supersonic turbulence (McKee & Tan 2003; Mac Low & Klessen 2004); (2) according to recent simulations of star formation in clusters (e.g. Bonnell et al. 1997, 2001), the accretion rate and in turn the mass of the forming star are strongly affected by the density of the molecular cloud…”
The initial conditions of star formation in the Ophiuchus main cloud: Kinematics of the protocluster condensations , (2007, methodology): “Note that the small value found here for the mean condensation velocity relative to the local gas (Vmean ∼ 0.3 km s−1) is also consistent with the predictions of the competitive accretion model during the gas-dominated phase of protocluster evolution (Bonnell et al. 2001a).”
Embedded Clusters in Molecular Clouds (2003, background): “The process is highly nonlinear and, even for a cluster with initially equal mass protostellar fragments, can lead to the development of a protostellar mass spectrum similar to that of the stellar IMF (Bonnell et al. 2001b, Klessen 2001).”
The Stellar Mass Spectrum from Non-Isothermal Gravoturbulent Fragmentation (2004, background): “This is due to protostellar accretion processes, as more and more gas gets turned into stars (see also, Bonnell et al. 2001b; Klessen 2001; Schmeja & Klessen 2004).”
The Birth of High-Mass Stars: Accretion and/or Mergers? (2005, background): “This effect, known as “competitive accretion”, can lead to run-away growth of the most massive objects in a forming cluster (Zinnecker 1982; Bonnell et al. 2001a, b).”
Accretion in stellar clusters and the collisional formation of massive stars (2002, methodology): “This extends a similar finding that gas accretion on its own is capable of explaining the IMF (Bonnell et al. 2001b).”
Toward Understanding Massive Star Formation (2007, background): “In an alternate scenario by Bonnell et al. (1997, 2001a), the compression phase is more of a transient phase due to the random motions in the selfgravitating cloud.”
COLLAPSE OF MASSIVE MAGNETIZED DENSE CORES USING RADIATION MAGNETOHYDRODYNAMICS: EARLY FRAGMENTATION INHIBITION (2011, methodology): “For instance, isothermal simulations (e.g., Bonnell et al. 2001; Bonnell & Bate 2006) and radiative calculations (Krumholz et al. 2007, 2009), magnetized ones (Wang et al. 2010; Hennebelle et al. 2011; Peters et al. 2011; Seifried et al. 2011) and even calculations including radiative ionization…”
Binary Mergers and Growth of Black Holes in Dense Star Clusters (2005, background): “…progenitors (Freitag et al. 2005); (2) there may be preferential formation of massive stars near the cluster center (see, e.g., Murray & Lin 1996; Bonnell et al. 2001); and (3) BH birth kicks are not expected to be large enough to displace the BHs into the cluster halo (or eject them from the…”
The importance of radiative feedback for the stellar initial mass function (2008, background): “It may originate from competitive accretion of fragments (Hoyle 1953; Larson 1978; Zinnecker 1982; Bonnell et al. 1997, 2001a; Bonnell et al. 2001b; Klessen, Burkert & Bate 1998; Myers 2000).”
The hierarchical formation of a stellar cluster (2003, background): “This process – termed competitive accretion – is a leading candidate to explain the apparently universal initial mass function (IMF) of stars (Bonnell et al. 2001c; Klessen 2001).”
Gravitational fragmentation and the formation of brown dwarfs in stellar clusters (2008, background): “This is more evident for the high-mass sinks where the vast majority of their final masses comes from the subsequent competitive accretion (Bonnell et al. 2001; Bonnell, Vine & Bate 2004; Bonnell & Bate 2006).”