The importance of radiative feedback for the stellar initial mass function

By Matthew R. Bate. 2008

212 citations recorded by the source corpus.

We investigate the effect of radiative feedback on the star formation process using radiation hydrodynamical simulations. We repeat the previous hydrodynamical star cluster formation simulations of Bate et al. and Bate & Bonnell, but we use a realistic gas equation of state and radiative transfer in the flux-limited diffusion approximation rather than the original barotropic equation of state. Whereas star formation in the barotropic simulations continued unabated until the simulations stopped, we find that radiative feedback, even from low-mass stars, were essentially terminates the production of new objects within low-mass dense molecular cloud cores after roughly one local dynamical time. Radiative feedback also dramatically decreases the propensity of massive circumstellar discs to fragment and inhibits fragmentation of other dense gas (e.g. filaments) close to existing protostellar objects. These two effects decrease the numbers of protostars formed by a factor of ≈4 compared with the original hydrodynamical simulations using the barotropic equation of state. In particular, whereas the original simulations produced more brown dwarfs than stars, the radiative feedback results in a ratio of stars to brown dwarfs of approximately 5:1, in much better agreement with observations. Most importantly, we find that although the characteristic stellar mass in the original calculations scaled linearly with the initial mean Jeans mass in the clouds, when radiative feedback is included the characteristic stellar mass is indistinguishable for the two calculations, regardless of the initial Jeans mass of the clouds. We thus propose that the reason the observed initial mass function appears to be universal in the local Universe is due to self-regulation of the star formation process by radiative feedback. We present an analytic argument showing how a characteristic mass may be derived that is relatively independent of initial conditions such as the cloud's density.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/bee5a1708dea223251ba6c872428c240896768c3

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Citations in the corpus

ANALYTICAL THEORY FOR THE INITIAL MASS FUNCTION. II. PROPERTIES OF THE FLOW (2009, background): “It is not excluded, however, that the low mass end of the IMF might be affected by secondary mechanisms such as, for instance, dynamical ejections and radiative feedback (Bate 2009) or massive disk fragmentation (Stamatellos & Whitworth 2009).”
Simulations of the grand design galaxy M51: a case study for analysing tidally induced spiral structure (2009, methodology): “…Yoshida & White 2001; Springel 2005), which has previously been applied to simulations of interacting galaxies (e.g. Cox et al. 2006; Jáchym et al. 2007), our code has predominantly been used for simulations of star formation (e.g. Bate, Bonnell & Bromm 2003; Price & Bate 2008; Bate 2009a,b).”
The Close Binary Fraction of Solar-type Stars Is Strongly Anticorrelated with Metallicity (2018, background): “The inability to directly fragment at small separations is consistent with previous studies that demonstrated that close binaries (a<10 au) could not have formed in situ (Boss 1986; Bate 1998, 2009a).”
MODELING THE EXTRAGALACTIC BACKGROUND LIGHT FROM STARS AND DUST (2009, background): “Although radiation hydrodynamic simulations indicate that radiative feedback could lead to a universal IMF in the local universe (Bate 2009), a detailed modeling of a large amount of Sloan Digital Sky Survey data indicates that fainter galaxies generally have an IMF which produces fewer massive…”
RADIATION-HYDRODYNAMIC SIMULATIONS OF THE FORMATION OF ORION-LIKE STAR CLUSTERS. II. THE INITIAL MASS FUNCTION FROM WINDS, TURBULENCE, AND RADIATION (2012, methodology): “…whether it be an imposed equation of state (e.g. Bate & Bonnell 2005; Jappsen et al. 2005) or the inclusion of radiative transfer, either without (Bate 2009b, 2012) or with (Krumholz et al. 2007a, 2010, 2011; Offner et al. 2009; Urban et al. 2010) the further step of including stellar radiation.”
Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation (2011, methodology): “Currently, the only published hydrodynamical calculations that resolve the opacity limit for fragmentation and produce large numbers of stars, brown dwarfs (>100) are those of Bate (2009a).”
Collapse, outflows and fragmentation of massive, turbulent and magnetized prestellar barotropic cores (2011, methodology): “The impact of radiative feedback on fragmentation has been investigated analytically by Krumholz (2006) and Krumholz & McKee (2008), and numerically by Krumholz et al. (2007, 2010), Bate (2009), Offner et al. (2009), Urban et al. (2010), Kuiper et al. (2010) and Peters et al. (2010abcd).”
Phantom: A Smoothed Particle Hydrodynamics and Magnetohydrodynamics Code for Astrophysics (2017, background): “Similarly, the sphng code (Benz et al., 1990; Bate, 1995) has been a workhorse for our group for simulations of star formation (e.g. Price & Bate, 2007, 2009; Price et al., 2012; Lewis et al., 2015) and accretion discs (e.g. Lodato & Rice, 2004; Cossins et al., 2009), contains a rich array of…”
CIRCUMVENTING THE RADIATION PRESSURE BARRIER IN THE FORMATION OF MASSIVE STARS VIA DISK ACCRETION (2010, background): “Previous theoretical models focused on different points of view, namely, the competitive accretion (Bonnell et al. 1998; Bonnell & Bate 2002; Bonnell et al. 2004; Bate 2009a, 2009b) and the turbulent core model (McKee & Tan 2003), but they agree on the formation of accretion disks.”
THE EFFECTS OF RADIATIVE TRANSFER ON LOW-MASS STAR FORMATION (2009, methodology): “As Bate (2009b) also neglected deuterium burning, the calculations represent a lower limit on the effects of radiative feedback.”
THE FORMATION OF LOW-MASS BINARY STAR SYSTEMS VIA TURBULENT FRAGMENTATION (2010, methodology): “In the upcoming sections we define our key dimensionless parameters, outline our testing scheme, describe our 1 Bate (2009) includes radiative transfer on numerically resolved scales, but not radiation feedback from nuclear or accretion luminosity of stars, which Offner et al. (2009) show is…”
Dynamic star formation in the massive DR21 filament (2010, background): “Support from magnetic fields (Hennebelle & Teyssier 2008) and/or radiation (Krumholz 2006, Bate 2009) could drastically limit the level of fragmentation and channel the global infall to fewer, more massive protostars (Bontemps et al. 2010).”
MODELING COLLAPSE AND ACCRETION IN TURBULENT GAS CLOUDS: IMPLEMENTATION AND COMPARISON OF SINK PARTICLES IN AMR AND SPH (2010, methodology): “Our models did not take into account the effects of radiation transfer, which is ex- pected to suppress fragmentation (Krumholz et al. 2007; Bate 2009).”
ERRATUM: “THE LUMINOSITY AND MASS FUNCTIONS OF LOW-MASS STARS IN THE GALACTIC DISK. II. THE FIELD” (2010, AJ, 139, 2679) (2010, result): “Recent numerical simulations have shown favorable agreement with our results (Bate 2009); however, most numerical simulations of star formation are restricted in sample size and suffer significant Poisson uncertainties.”
Before the first supernova: combined effects of H II regions and winds on molecular clouds (2014, unknown): “Numerous recent studies (e.g Price & Bate 2009; Wang et al. 2010; Vázquez-Semadeni et al. 2011; Padoan & Nordlund 2011; Peters et al. 2011; Federrath & Klessen 2012; Myers et al. 2014) have found that the support provided at intermediate and large scales by magnetic fields slows star formation…”
On the diversity and statistical properties of protostellar discs (2018, methodology): “Bate (2009a, 2012) present statistics on the misalignment angles of orbits in triple systems, and the misalignments between sink particle spins and orbits in binary systems, both of which display some similar trends to observed systems.”
Importance of the Initial Conditions for Star Formation - I. Cloud Evolution and Morphology (2010, background): “Changes in the equation of state, in particular if the gas becomes optically thick, will break the scale-free collapse (e.g. Jappsen et al. 2005; Krumholz et al. 2007; Bate 2009c).”
Global hierarchical collapse in molecular clouds. Towards a comprehensive scenario (2019, methodology): “Numerical simulations using a variety of schemes and setups have successfully reproduced the high mass end of the IMF, with a slope ∼ −1, close to the −1.3 canonical value of Salpeter (e.g., Bate 2009a; Bonnell et al. 2011).”
MAPPING THE SHORES OF THE BROWN DWARF DESERT. II. MULTIPLE STAR FORMATION IN TAURUS–AURIGA (2011, methodology): “Both of these results can be seen in hydrodynamic simulations (Bate et al. 2000; Delgado-Donate et al. 2004; Bate 2009).”