THE EFFECTS OF RADIATIVE TRANSFER ON LOW-MASS STAR FORMATION

By Stella S. R. Offner, Richard Klein, C. McKee, Mark R. Krumholz. 2009

227 citations recorded by the source corpus.

Forming stars emit a substantial amount of radiation into their natal environment. We use ORION, an adaptive mesh refinement (AMR) three-dimensional gravito-radiation-hydrodyanics code, to simulate low-mass star formation in a turbulent molecular cloud. We compare the distributions of stellar masses, accretion rates, and temperatures in the cases with and without radiative transfer, and we demonstrate that radiative feedback has a profound effect on accretion, multiplicity, and mass by reducing the number of stars formed and the total rate at which gas turns into stars. We also show that once the star formation reaches a steady state, protostellar radiation is by far the dominant source of energy in the simulation, exceeding viscous dissipation and compressional heating by at least an order of magnitude. Calculations that omit radiative feedback from protstars significantly underestimate the gas temperature and the strength of this effect. Although heating from protostars is mainly confined to the protostellar cores, we find that it is sufficient to suppress disk fragmentation that would otherwise result in very low-mass companions or brown dwarfs. We demonstrate that the mean protostellar accretion rate increases with the final stellar mass so that the star formation time is only a weak function of mass.

Subfields: Astronomy and Astrophysics, Physical and Theoretical Chemistry, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/9304719cd63de44bb63d349b0e5dc7de46800202

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Citations in the corpus

The CO-H2 Conversion Factor in Disc Galaxies and Mergers (2011, background): “The code relies on implicit dissipationrather than an explicit viscosity, but we can estimate the viscous heating rate produced by that implicit dissipation by noting that the Reynolds number must be∼ 1 on the resolution scale of the code (Offner et al. 2009).”
Gravitational Instabilities in Circumstellar Disks (2016, methodology): “Indeed irradiated disk simulations have more similarities to isothermal simulations than barotropic or cooling simulations (Krumholz et al. 2009; Offner et al. 2009).”
ON THE ROLE OF DISKS IN THE FORMATION OF STELLAR SYSTEMS: A NUMERICAL PARAMETER STUDY OF RAPID ACCRETION (2009, background): “Isothermal equation of state Many simulations have shown the dramatic effects that thermodynamics have on disk behavior (Boss et al. 2000; Gammie 2001; Rice et al. 2005; Lodato & Rice 2005; Boley et al. 2006; Krumholz et al. 2007; Offner et al. 2009).”
Galaxies on FIRE (Feedback In Realistic Environments): stellar feedback explains cosmologically inefficient star formation (2013, background): “…these have necessarily been restricted to very small systems, either single molecular clouds/star clusters (e.g. Krumholz et al. 2007, 2011; Offner et al. 2009, 2011; HarperClark & Murray 2011; Bate 2012), or the “first stars” (e.g. Wise et al. 2012; Pawlik et al. 2013; Muratov et al.…”
Global hierarchical collapse in molecular clouds. Towards a comprehensive scenario (2019, background): “…problem then becomes to avoid an excessive formation of these objects by inclusion of radiative transfer to adequately model the gas heating from the accretion shock onto the hydrostatic core, in order to prevent excessive fragmentation (e.g., Krumholz et al. 2007; Bate 2009b; Offner et al. 2009).”
Collapse, outflows and fragmentation of massive, turbulent and magnetized prestellar barotropic cores (2011, methodology): “For low mass stars, while Offner et al. (2009) conclude that the protostellar feedback is still sufficient to heat the gas substantially and therefore stabilizing the disk efficiently, Stamatellos et al. (2009) conclude that the disks are fragmenting.”
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.”
Building up the Population III initial mass function from cosmological initial conditions (2016, methodology): “For the initial protostellar phases, we first set Lint = LHay, similar to the prescription described in Offner et al. (2009).”
Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation (2011, background): “More recent calculations have the investigated effects of additional physical processes on the origin of the IMF such as radiative transfer (Offner et al. 2009; Urban, Martel & Evans 2010; Krumholz, Klein & McKee 2011), but these calculations also employ sink particles with accretion radii of…”
Globular clusters as the relics of regular star formation in ‘normal’ high-redshift galaxies (2015, background): “…Krumholz, Klein & McKee 2012) and the merging of stellar aggregates (Maschberger et al. 2010; Fujii, Saitoh & Portegies Zwart 2012), in which gravitationally bound structure naturally arises at the highest-density peaks (e.g. Offner et al. 2009; Kruijssen et al. 2012a; Girichidis et al. 2012).”
THE RUNTS OF THE LITTER: WHY PLANETS FORMED THROUGH GRAVITATIONAL INSTABILITY CAN ONLY BE FAILED BINARY STARS (2009, background): “(Rafikov & De Colle 2006; Offner et al. 2009).”
The Formation and Early Evolution of Low-Mass Stars and Brown Dwarfs (2012, background): “…with other companions or nearby stars (Bate & Bonnell 2005; Bate, Bonnell & Bromm 2002, 2003; Goodwin & Whitworth 2007; Offner, Klein & McKee 2008; Offner et al. 2009; Rice et al. 2003; Shen et al. 2010; Stamatellos, Hubber & Whitworth 2007; Stamatellos & Whitworth 2009; Stamatellos et al. 2011;…”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, background): “…environments), and generate galactic chimneys and super-bubbles c© 0000 RAS, MNRAS 000, 000–000 that generate fountains and super-winds (e.g. Krumholz et al. 2007, 2011; Offner et al. 2009, 2011; Harper-Clark & Murray 2011; Bate 2012; Wise et al. 2012; Pawlik et al. 2013; Muratov et al. 2013).”
On the diversity and statistical properties of protostellar discs (2018, methodology): “Only the calculations of Bate (e.g. Bate, Bonnell & Bromm 2002b, 2003; Bate & Bonnell 2005; Bate 2009a,b, 2012) and Offner (Offner, Klein & McKee 2008; Offner et al. 2009) have tried to bridge these two regimes by using small sink particles (∼< 10 au).”
OUTFLOW FEEDBACK REGULATED MASSIVE STAR FORMATION IN PARSEC-SCALE CLUSTER-FORMING CLUMPS (2009, methodology): “The flow so close to a forming star may be strongly affected by radiative heating (Offner et al. 2009; Bate 2009; Smith et al. 2009), which is not included in our simulations.”
MAPPING THE SHORES OF THE BROWN DWARF DESERT. II. MULTIPLE STAR FORMATION IN TAURUS–AURIGA (2011, methodology): “Recent updates to theoretical simulations may have solved these controversies; new model runs that incorporate magnetic fields and radiative feedback seem to produce systems with a few larger stars (Bate 2009; Offner et al. 2009), rather than the many brown dwarfs seen in early models.”
LIMITING ACCRETION ONTO MASSIVE STARS BY FRAGMENTATION-INDUCED STARVATION (2010, background): “In addition, radiative feedback also is able to reduce the number of fragments that form during the collapse of high-mass cores (Krumholz et al. 2007b) as well as lowmass cores (Offner et al. 2009).”
THE FORMATION OF LOW-MASS BINARY STAR SYSTEMS VIA TURBULENT FRAGMENTATION (2010, methodology): “(The initial subvirial velocity dispersion of the stars predisposes young clusters to dynamical interactions that will impact the final binary distribution; Bate et al. 2003; Offner et al. 2009a.)”