Magnetically Regulated Star Formation in Three Dimensions: The Case of the Taurus Molecular Cloud Complex

By F. Nakamura, Zhi-Yun Li. 2008

172 citations recorded by the source corpus.

We carry out three-dimensional MHD simulations of star formation in turbulent, magnetized clouds, including ambipolar diffusion and feedback from protostellar outflows. The calculations focus on relatively diffuse clouds threaded by a strong magnetic field capable of resisting severe tangling by turbulent motions and retarding global gravitational contraction in the cross field direction. They are motivated by observations of the Taurus molecular cloud complex (and, to a lesser extent, Pipe Nebula), which shows an ordered large-scale magnetic field, as well as elongated condensations that are generally perpendicular to the large-scale field. We find that stars form in earnest in such clouds when enough material has settled gravitationally along the field lines that the mass-to-flux ratios of the condensations approach the critical value. Only a small fraction (of order 1% or less) of the nearly magnetically critical, condensed material is turned into stars per local free-fall time, however. The slow star formation takes place in condensations that are moderately supersonic; it is regulated primarily by magnetic fields, rather than turbulence. The quiescent condensations are surrounded by diffuse halos that are much more turbulent, as observed in the Taurus complex. Strong support for magnetic regulation of star formation in this complex comes from the extremely slow conversion of the already condensed, relatively quiescent C18O gas into stars, at a rate 2 orders of magnitude below the maximum, free-fall value. We analyze the properties of dense cores, including their mass spectrum, which resembles the stellar initial mass function.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/af7a4cb5bd34204581fcb161ef71e378b2e1b275

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Citations in the corpus

WHAT DRIVES THE EXPANSION OF GIANT H ii REGIONS?: A STUDY OF STELLAR FEEDBACK IN 30 DORADUS (2010, background): “…(e.g., Whitworth 1979; Dale et al. 2005), the hot gas shock heated by stellar winds and supernovae (e.g., Yorke et al. 1989; Harper-Clark & Murray 2009), and protostellar outflows/jets (e.g., Quillen et al. 2005; Cunningham et al. 2006; Li & Nakamura 2006; Nakamura & Li 2008; Wang et al. 2010).”
Accretion-driven turbulence as universal process: galaxies, molecular clouds, and protostellar disks (2009, background): “…flows (Hunter et al. 1986; Vishniac 1994), or driven by internal sources such as protostellar outflows (Li & Nakamura 2006; Banerjee et al. 2007; Nakamura & Li 2008; Wang et al. 2010) or expanding HII regions (Matzner 2002) or supernovae (Mac Low & Klessen 2004), is still subject to…”
THE STAR FORMATION RATE OF TURBULENT MAGNETIZED CLOUDS: COMPARING THEORY, SIMULATIONS, AND OBSERVATIONS (2012, background): “On smaller scales, jets and outflows from young stellar objects have been suggested to drive turbulence (Norman & Silk 1980; Banerjee et al. 2007; Nakamura & Li 2008; Cunningham et al. 2009; Carroll et al. 2010; Wang et al. 2010).”
AN IMPRINT OF MOLECULAR CLOUD MAGNETIZATION IN THE MORPHOLOGY OF THE DUST POLARIZED EMISSION (2013, methodology): “Nevertheless, the HRO analysis can be extended to simulations including more complex realizations of molecular clouds (Nakamura & Li 2008; Hennebelle et al. 2008).”
FILAMENTARY STRUCTURE OF STAR-FORMING COMPLEXES (2009, background): “17 Hubs and filaments are also seen in the simulations of a magnetized cloud whose turbulence dissipates, causing the cloud to condense along its field lines into a dense layer (Nakamura and Li 2008).”
A NEW JEANS RESOLUTION CRITERION FOR (M)HD SIMULATIONS OF SELF-GRAVITATING GAS: APPLICATION TO MAGNETIC FIELD AMPLIFICATION BY GRAVITY-DRIVEN TURBULENCE (2011, background): “The power of jets and outflows from low-mass stars is also enormous, and may thus contribute to the turbulence driving on intermediate and small scales (e.g., Tan & Blackman 2004; Nakamura & Li 2008; Li et al. 2010; Carroll et al. 2010).”
On the universality of supersonic turbulence (2013, background): “Wind, jets and outflows from young stellar objects have also been suggested to drive turbulence on smaller scales (Norman & Silk 1980; Banerjee, Klessen & Fendt 2007; Nakamura & Li 2008; Cunningham et al. 2009; Carroll, Frank & Blackman 2010; Wang et al. 2010; Moraghan, Kim & Yoon 2013).”