Formation and evolution of primordial protostellar systems

By Thomas Greif, Volker Bromm, P. C. Clark, S. Glover, Rowan J. Smith, Ralf Klessen, Naoki Yoshida, Volker Springel. 2012

262 citations recorded by the source corpus.

We investigate the formation of the first stars at the end of the cosmic dark ages with a suite of three-dimensional, moving-mesh simulations that directly resolve the collapse of the gas beyond the formation of the first protostar at the centre of a dark matter minihalo. The simulations cover more than 25 orders of magnitude in density and have a maximum spatial resolution of 0.05 R⊙, which extends well below the radius of individual protostars and captures their interaction with the surrounding gas. In analogy to previous studies that employed sink particles, we find that the Keplerian disc around the primary protostar fragments into a number of secondary protostars, which is facilitated by H2 collisional dissociation cooling and collision-induced emission. The further evolution of the protostellar system is characterized by strong gravitational torques that transfer angular momentum between the secondary protostars formed in the disc and the surrounding gas. This leads to the migration of about half of the secondary protostars to the centre of the cloud in a free-fall time, where they merge with the primary protostar and enhance its growth to about five times the mass of the second most massive protostar. By the same token, a fraction of the protostars obtain angular momentum from other protostars via N-body interactions and migrate to higher orbits. On average, only every third protostar survives until the end of the simulation. However, the number of protostars present at any given time increases monotonically, suggesting that the system will continue to grow beyond the limited period of time simulated here.

View Paper: https://www.semanticscholar.org/paper/84433c05f900d2a2fa4de75cb83f67ace1fd7d9a

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

Citations in the corpus

Titans of the early Universe: The Prato statement on the origin of the first supermassive black holes (2018, background): “As the disk grows in mass it may become gravitationally unstable, fragment, and form multiple objects (Clark et al. 2011a, 2011b; Smith et al. 2011; Greif et al. 2012; Regan et al. 2014; Sakurai et al. 2016).”
FORMATION OF MASSIVE PRIMORDIAL STARS: INTERMITTENT UV FEEDBACK WITH EPISODIC MASS ACCRETION (2015, background): “…these studies may suffer from limited spatial resolution; the numbers of cells assigned per Jeans length are 8 and 32 in Machida & Doi (2013) and Greif et al. (2012), respectively, whereas it is known that significantly higher resolution is required to also capture the turbulent motions…”
The birth of a galaxy – III. Propelling reionization with the faintest galaxies (2014, methodology): “On a similar topic, we used a characteristic mass of 100 M for our Pop III IMF, which is somewhat higher than recent Pop III star formation simulations that find characteristic masses around tens of M (Turk, Abel & O’Shea 2009; Stacy, Greif & Bromm 2010; Greif et al. 2011b, 2012; Susa 2013).”
Improving the convergence properties of the moving-mesh code AREPO (2015, background): “G A ] 2014; Genel et al. 2014), as well as in first star formation (e.g. Greif et al. 2011, 2012; Smith et al. 2014), and to a smaller extent in stellar astrophysics (Pakmor et al. 2013) and in problems related to planet formation (Duffell & MacFadyen 2012; Muñoz et al. 2014, 2015).”
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution (2015, background): “However, there is an opposite effect; a large fraction of the protostars could rapidly migrate inward due to c© 2015 RAS, MNRAS 000, 1–22 gravitational torque, resulting in frequent stellar mergers at the cloud centre (e.g., Greif et al. 2012; Vorobyov et al. 2013).”
THE MASS SPECTRUM OF THE FIRST STARS (2014, methodology): “We set the sink radius rsink to 30 AU, but the previous higher-resolution studies of rsink 1 AU (with short time integration) revealed that the disk within 30 AU also fragments into secondary stars (e.g., Clark et al. 2011b; Greif et al. 2012).”
ONE HUNDRED FIRST STARS: PROTOSTELLAR EVOLUTION AND THE FINAL MASSES (2013, methodology): “It has become possible to perform ab initio numerical simulations to follow this process (e.g., Abel et al. 2002; Yoshida et al. 2008; Greif et al. 2012).”
Building up the Population III initial mass function from cosmological initial conditions (2016, background): “The simulation of Greif et al. (2012) explored primordial star formation with an extremely high spatial resolution of 0.05 R⊙.”
Physical Processes in the Interstellar Medium (2014, background): “…star formation (see e.g. Smith et al., 2009), other work suggests that low-mass stars can form even at very high redshifts (see e.g. Clark et al., 2011; Greif et al., 2011, 2012; Dopcke et al., 2013) by the fragmentation of the accretion disk surrounding the central star (see also Section 6.4).”
Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionization (2016, background): “Later, several groups point out that gas clumps may be fragmented further reducing the characteristic mass to ∼ 40 M (Turk et al. 2009; Greif et al. 2012) However, recent radiationhydrodynamics simulations report that several tens to a thousand solar masses of gas may collapse to form a Pop III…”
Formation of Supermassive Black Hole Seeds (2016, background): “Some of the clumps from disk fragmentation migrate inward and merge with the central protostar while the rest survive PASA (2016) doi:10.1017/pas.2016.xxx to form a multiple system (Greif et al. 2012; Stacy et al. 2016).”
Black hole formation in the early Universe (2013, background): “In the presence of high-mass accretion rates and efficient cooling, gravitational torques may not be sufficient to transport the gas through the disc leading to fragmentation (Clark et al. 2011; Greif et al. 2012).”
The First Stars (2012, background): “Greif et al. (2012) have recently published the results of an initial effort along these lines, but were only able to simulate the first ten years of the evolution of the disk, owing the extremely high computational cost of the calculation.”
Modeling the Radio Background from the First Black Holes at Cosmic Dawn: Implications for the 21 cm Absorption Amplitude (2018, background): “Many studies find that the first protostellar disks fragment into small clumps (Stacy et al. 2010; Clark et al. 2011; Greif et al. 2011b, 2012), but it is still unclear whether these small fragments typically migrated to the center of the disk, forming a 100–1000Me star, or remained apart, forming…”
Possible indirect confirmation of the existence of Pop III massive stars by gravitational wave (2014, background): “Pop III stars are the first stars after the big bang which are formed from metal-free gas (Omukai & Nishi 1998; Abel, Bryan & Norman 2002; Bromm, Coppi & Larson 2002; Yoshida, Omukai & Hernquist 2008; Greif et al. 2012).”