Star formation and the origin of stellar masses

Podsiadlowski, Philipp; Price, Nigel M.

doi:10.1038/359305a0

Cited by 10 publications

(9 citation statements)

References 20 publications

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“…The nature of the mass segregation to be expected is determined by whether or not interactions act to enhance or to halt the accretion process. Podsiadlowski & Price (1992) propose a picture in which the initial stages of star formation closely resemble the picture of Shu et al (1987). In their model, however, accretion onto a protostellar core is terminated when the infalling gas cloud is disrupted by a close encounter with another protostellar core.…”

Section: Discussionmentioning

confidence: 99%

Mass Segregation in Young Large Magellanic Cloud Clusters. I. NGC 2157

Fischer¹,

Pryor²,

Murray³

et al. 1998

The Astronomical Journal

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We have carried out WFPC2 V -and I-band imaging of the young LMC cluster NGC 2157. Construction of a color-magnitude diagram and isochrone fitting yields an age of τ = 10 8 yrs, a reddening E(B − V ) = 0.1 and a distance modulus of 18.4 mag. Our data covers the mass range 0.75 M ⊙ ≤ m ≤ 5.1 M ⊙ . We find that the cluster mass function changes significantly from the inner regions to the outer regions, becoming steeper (larger number of low mass stars relative to high mass stars) at larger radii.The age of NGC 2157 is comparable to its two-body relaxation timescale only in the cluster core. The observed steepening of the mass function at larger radii is therefore most likely an initial condition of the cluster stars. Such initial conditions are predicted in models of cluster star formation in which dissipative processes act more strongly upon more massive stars.

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Section: Discussionmentioning

confidence: 99%

Mass Segregation in Young Large Magellanic Cloud Clusters. I. NGC 2157

Fischer¹,

Pryor²,

Murray³

et al. 1998

The Astronomical Journal

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“…These models reproduce reasonably well many of the characteristics of Galactic starforming regions. Interestingly, the author finds that protostellar accretion is often terminated by dynamical interactions, and therefore that dynamics plays an important role in shaping the stellar initial mass function (IMF) (Podsiadlowski & Price 1992), at least in the dense clusters considered in this study. The importance of dynamics and multiplicity during the star formation process has also been confirmed observationally.…”

Section: Introductionmentioning

confidence: 92%

The dynamical significance of triple star systems in star clusters

Leigh

Geller

2013

Monthly Notices of the Royal Astronomical Society

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Over the last few decades, observational surveys have revealed that high-order multiple-star systems (e.g. triples, quadruples, etc.), and triples in particular, are common in our Galaxy. In this paper, we consider the dynamical significance of this transformation in our understanding of stellar multiplicity. Using empirically constrained binary and triple fractions in those star clusters for which these values are available in the literature, we compare analytic rates for encounters involving single, binary, and triple stars. Our results show that, even for relatively low triple fractions, dynamical interactions involving triples occur roughly as often as encounters involving either single or binary stars alone, particularly in low-mass star clusters. More generally, using empirically-derived multiple star catalogues for the young star-forming association Taurus-Auriga and the Galactic field, we show that the data are consistent with the gravitationally-focused cross section for encounters increasing with increasing multiplicity. Consequently, triple stars, and even higher-order multiples, could be more important than previously realized for a number of astrophysical phenomena, including the formation and destruction of compact binaries and various types of stellar exotica, and the dynamical evolution of star clusters.

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“…The role played by several physical processes on the origin and evolution of the PSCMF has been extensively studied both theoretically and numerically. The major physical processes considered are: a) gravitational fragmentation (e.g., Zinnecker 1984;Larson 1985;Klessen et al 1998;Klessen & Burkert 2001), turbulent fragmentation (Elmegreen 1993;Padoan 1995;Padoan et al 1997;Padoan & Nordlund 2002;Padoan et al 2007), gas accretion (Zinnecker 1982;Larson 1992;Bonnell et al 1997;Klessen & Burkert 2000;Bonnell et al 2001a,b;Basu & Jones 2004;Dobbs et al 2005;Clark & Bonnell 2006;Banerjee et al 2006;, Heitsch et al 2008Clark et al 2008;Dib et al 2008b, Offner et al 2008, Myers 2009, cores or star coalescence (Field & Saslaw 1965;Nakano 1966;Silk & Takahashi 1979;Podsiadlowski & Price 1992;Price & Podsiadlowski 1995;Elmegreen & Shadmehri 2003;Elmegreen 2004;Shadmehri 2004;Davies et al 2006;McMillan et al 2007;Kitsionas & Whitworth 2007;Dib 2007;Dib et al 2007aDib et al ,2008a, ejection of predominantly low mass stars (e.g., Bate et al 2002;…”

Section: Origin Of the Imfmentioning

confidence: 99%

“…The major physical processes considered are (i) gravitational fragmentation (e.g. Zinnecker 1984; Larson 1985; Klessen, Burkert & Bate 1998; Klessen & Burkert 2001), turbulent fragmentation (Elmegreen 1993; Padoan 1995; Padoan, Nordlund & Jones 1997; Padoan & Nordlund 2002, hereafter PN02; Padoan et al 2007), gas accretion (Zinnecker 1982; Larson 1992; Bonnell et al 1997; Klessen & Burkert 2000; Bonnell et al 2001a,b; Basu & Jones 2004; Bate & Bonnell 2005; Dobbs, Bonnell & Clark 2005; Banerjee, Pudritz & Anderson 2006; Bonnell & Bate 2006; Clark & Bonnell 2006; Bonnell et al 2007a; Clark, Bonnell & Klessen 2008; Heitsch et al 2008; Dib et al 2008b; Offner, Klein & McKee 2008; Myers 2009), cores or star coalescence (Field & Saslaw 1965; Nakano 1966; Silk & Takahashi 1979; Podsiadlowski & Price 1992; Price & Podsiadlowski 1995; Bonnell, Bate & Zinnecker 1998; Bonnell & Bate 2002; Elmegreen & Shadmehri 2003; Elmegreen 2004; Shadmehri 2004; Davies et al 2006; Dib 2007; Kitsionas & Whitworth 2007; McMillan et al 2007; Dib et al 2007a, 2008a), ejection of predominantly low‐mass stars (e.g. Bate, Bonnell & Bromm 2002; Goodwin, Whitworth & Ward‐Thompson 2004; Bate & Bonnell 2005) and magnetic fields (Shu et al 2004; Dib et al 2007b; Nakamura & Li 2008; Price & Bate 2008; Kunz & Mouschovias 2009).…”

Section: Introductionmentioning

confidence: 99%

The IMF of stellar clusters: effects of accretion and feedback

Dib

Shadmehri

Padoan

et al. 2010

Monthly Notices of the Royal Astronomical Society

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(abridged) We develop a model which describes the coevolution of the mass function of dense cores and of the IMF in a protocluster clump. In the model, cores injected in the clump evolve under the effect of gas accretion. Accretion onto the cores follows a time-dependent accretion rate that describes accretion in a turbulent medium. Once the accretion timescales of cores exceed their contraction timescales, they are turned into stars. We include the effect of feedback by the newly formed massive stars through their stellar winds. A fraction of the wind's energy is assumed to counter gravity and disperse the gas from the protocluster and as a consequence, quench further star formation. The latter effect sets the final IMF of the cluster. We apply our model to a clump that is expected to resemble the progenitor clump of the Orion Nebula Cluster (ONC). Our model is able to reproduce both the shape and normalization of the ONC's IMF and the mass function of dense cores in Orion. The complex features of the ONC's IMF,i.e., a shallow slope in the mass range ~0.3-2.5 Msol,a steeper slope in the mass range ~2.5-12 Msol, and a nearly flat tail at the high mass end are reproduced. The model predicts a 'rapid' star formation process with an age spread for the stars of 2.3 10^5 yr which is consistent with the fact that 80% of the ONC's stars have ages of <=0.3 Myr. The model predicts a primordial mass segregation with the most massive stars being born in the region between 2-4 times the core radius of the cluster. In parallel, the model also reproduces, simultaneously, the mass function of dense cores in Orion. We study the effects of varying the model parameters on the resulting IMF and show that the IMF of stellar clusters is expected to show significant variations, provided variations in the clumps and cores properties exist.Comment: accepted to MNRAS. 22 pages, 17 figures. 2 new sections added to better present the model parameters and compare to previous work. Some figures are now better presented. Main conclusions unchange

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Star formation and the origin of stellar masses

Cited by 10 publications

References 20 publications

Mass Segregation in Young Large Magellanic Cloud Clusters. I. NGC 2157

Mass Segregation in Young Large Magellanic Cloud Clusters. I. NGC 2157

The dynamical significance of triple star systems in star clusters

The IMF of stellar clusters: effects of accretion and feedback

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