The impact of magnetic fields on single and binary star formation

By Daniel J. Price, Matthew R. Bate. 2007

203 citations recorded by the source corpus.

We have performed magnetohydrodynamics (MHD) simulations of the collapse and fragmentation of molecular cloud cores using a new algorithm for MHD within the smoothed particle hydrodynamics (SPH) method that enforces the zero magnetic divergence constraint. We find that the support provided by magnetic fields over thermal pressure alone has several important effects on fragmentation and the formation of binary and multiple systems, and on the properties of massive circumstellar discs. The extra support suppresses the tendency of molecular cloud cores to fragment due to either initial density perturbations or disc fragmentation. Furthermore, unlike most previous studies, we find that magnetic pressure plays the dominant role in inhibiting fragmentation rather than magnetic tension or magnetic braking. In particular, we find that if the magnetic field is aligned with the rotation axis of the molecular cloud core, the effects of the magnetic field on fragmentation and disc structure are almost entirely due to magnetic pressure, while if the rotation axis is initially perpendicular to the magnetic field, magnetic tension plays a greater role and can actually aid fragmentation. Despite these effects, and contrary to several past studies, we find that strongly perturbed molecular cloud cores are able to fragment to form wide binary systems even in the presence of quite strong magnetic fields. For massive circumstellar discs, we find that slowing of the collapse caused by the magnetic support decreases the mass infall rate on to the disc and, thus, weakens gravitational instabilities in young massive circumstellar discs. This not only reduces the likelihood that they will fragment, but also decreases the importance of spiral density waves in providing angular momentum transport and in promoting planet formation.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ad0e2d4146eaee72cafe3ad4482e0b6a75cdd438

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Citations in the corpus

Smoothed particle hydrodynamics and magnetohydrodynamics (2010, background): “[82,27,50], most notably in star formation e.”
A NEW JEANS RESOLUTION CRITERION FOR (M)HD SIMULATIONS OF SELF-GRAVITATING GAS: APPLICATION TO MAGNETIC FIELD AMPLIFICATION BY GRAVITY-DRIVEN TURBULENCE (2011, methodology): “…artificial fragmentation found by Truelove et al. (1997) and frequently applied in simulations involving self-gravity with grid codes (e.g., Krumholz et al. 2004) and correspondingly with particle codes (e.g., Bate et al. 1995; Price & Bate 2007; Federrath et al. 2010a, and references therein).”
Disk formation during collapse of magnetized protostellar cores (2009, background): “Notable exceptions are the works of Machida et al. (2006), who explored the influence of a non zero angle between the magnetic field axis and the rotation axis, and Price & Bate (2007) who considered the case where the two axes are perpendicular.”
The effect of magnetic fields on star cluster formation (2008, methodology): “Thus, for example, we are not able at this resolution to confidently assert that we have accurately captured the influence of the magnetic field on the fragmentation of individual cores (e.g. as in Price & Bate 2007).”
Physical Processes in the Interstellar Medium (2014, background): “…and their parent clouds (Nakamura & Li, 2007; Krumholz et al., 2007b), influence the properties of protostellar disks due to magnetic braking (Price & Bate, 2007a; Mellon & Li, 2009; Hennebelle & Ciardi, 2009; Seifried et al., 2011, 2012a,b, 2013), or slow down the overall evolution (Heitsch…”
Inefficient star formation through turbulence, magnetic fields and feedback (2015, background): “Simulation work by e.g., Price & Bate (2007) and Hennebelle & Teyssier (2008) suggested that magnetic fields can suppress fragmentation on small scales and hence influence the shape of the initial mass function of stars.”
THE INTERPLAY OF MAGNETIC FIELDS, FRAGMENTATION, AND IONIZATION FEEDBACK IN HIGH-MASS STAR FORMATION (2010, background): “…of magnetic pressure and tension forces providing additional support to counteract gravitational collapse (Ziegler 2005; Banerjee & Pudritz 2006; Price & Bate 2007; Hennebelle & Fromang 2008; Hennebelle & Teyssier 2008; Hennebelle & Ciardi 2009; Commerçon et al. 2010; Bürzle et al. 2010).”
THE STAR FORMATION RATE OF TURBULENT MAGNETIZED CLOUDS: COMPARING THEORY, SIMULATIONS, AND OBSERVATIONS (2012, background): “…molecular clouds, magnetic fields seem to reduce fragmentation significantly (see Figure 4), thus potentially having a strong impact on the mass distribution of cores and stars (see also Price & Bate 2007; Hennebelle & Teyssier 2008; Bürzle et al. 2011; Peters et al. 2011; Hennebelle et al. 2011).”
THE FORMATION OF LOW-MASS BINARY STAR SYSTEMS VIA TURBULENT FRAGMENTATION (2010, background): “…using 3D ideal magnetohydrodynamics (MHD) find that the inclusion of magnetic fields suppresses disk fragmentation in the parameter space applicable to low-mass star formation (Price & Bate 2007; Hennebelle & Teyssier 2008), a result that is complementary to the role we find for radiative feedback.”
Smoothed Particle Hydrodynamics in Astrophysics (2010, background): “Although thishas been shown to work reasonably well in a number of simple test problems and also ha been used in some realworld applications (Price & Bate, 2007; Kotarba et al., 2009), it likely has significant problems in general MHD dynamics, as a result of the noise in SPH and the inability of…”
Stellar, brown dwarf and multiple star properties from hydrodynamical simulations of star cluster formation (2008, background): “Recently, Price & Bate (2007) showed that stronger magnetic fields generally inhibit disc formation and binary formation (see also Hennebelle & Fromang 2008; Hennebelle & Teyssier 2008).”
Magnetic processes in a collapsing dense core II. Fragmentation. Is there a fragmentation crisis (2007, methodology): “As demonstrated in this paper and in Price & Bate (2007), fragmentation is possible in such a situation.”
Simulations of the grand design galaxy M51: a case study for analysing tidally induced spiral structure (2009, background): “More recently magnetic fields have been included (Price & Monaghan 2005; Price & Bate 2007), although these are not used in the current paper.”
THE EFFECTS OF RADIATIVE TRANSFER ON LOW-MASS STAR FORMATION (2009, background): “Numerical simulations have demonstrated that the presence of magnetic fields may suppress disk fragmentation by supplying additional pressure support (Machida et al. 2008; Price & Bate 2007, 2008).”
Stellar, brown dwarf and multiple star properties from a radiation hydrodynamical simulation of star cluster formation (2011, methodology): “…smoothed particle hydrodynamics (SPH) code based on the original version of Benz (1990; Benz et al. 1990), but substantially modified as described in Bate et al. (1995), Whitehouse, Bate & Monaghan (2005), Whitehouse & Bate (2006), Price & Bate (2007), and parallelized using both OpenMP and MPI.”
Magnetic processes in a collapsing dense core I. Accretion and ejection (2007, unknown): “…developments have been realized and various 2D (Nakamura et al. 1995, Tomisaka 1998, Allen et al. 2003) as well as 3D numerical calculations have been performed (Hosking & Whitworth 2004, Machida et al. 2005, 2007, Ziegler 2005, Banerjee & Pudritz 2006, Fromang et al. 2006, Price & Bate 2007).”
ANALYTICAL THEORY FOR THE INITIAL MASS FUNCTION. II. PROPERTIES OF THE FLOW (2009, background): “…magnetic field, which has been shown to severely inhibit disk fragmentation (Machida et al. 2005, 2008, Hennebelle & Teyssier 2008, Price & Bate 2008) or even to prevent disk formation by magnetic braking (Galli et al. 2006, Price & Bate 2007, Hennebelle & Fromang 2008, Mellon & Li 2008a,b).”
On the diversity and statistical properties of protostellar discs (2018, background): “…of a core is aligned with a global field that is anchored at large distances from the centre of the core (Allen et al. 2003; Galli et al. 2006; Price & Bate 2007; Mellon & Li 2008; Hennebelle & Fromang 2008; Duffin & Pudritz 2009; Dapp & Basu 2010; Machida et al. 2011; Li et al. 2011; Dapp et…”
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…”
The importance of radiative feedback for the stellar initial mass function (2008, background): “Recently, Price & Bate (2007) showed that stronger magnetic fields generally inhibit disc formation and binary formation (see also Hennebelle & Fromang 2008; Hennebelle & Teyssier 2008).”