On the power - law tail in the mass function of protostellar condensations and stars
Nov, 20035 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 347 (2004) L47
e-Print:
- astro-ph/0311365 [astro-ph]
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Abstract: (arXiv)
We explore the idea that the power-law tail in the mass function of protostellar condensations and stars arises from the accretion of ambient cloud material on to a condensation, coupled with a nonuniform (exponential) distribution of accretion lifetimes. This model allows for the generation of power-law distributions in all star-forming regions, even if condensations start with a lognormal mass distribution, as may be expected from the central limit theorem, and supported by some recent numerical simulations of turbulent molecular clouds. For a condensation mass with growth rate , an analytic three-parameter probability density function is derived: it resembles a lognormal at low mass and has a pure power-law high-mass tail. An approximate power-law tail is also expected for other growth laws, and we calculate the distribution for the plausible case . Furthermore, any single time snapshot of the masses of condensations that are still accreting (and are of varying ages) also yields a distribution with a power-law tail similar to that of the IMF.References(18)
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