The formation of stellar clusters in turbulent molecular clouds: Effects of the equation of state

Yuexing Li, Ralf S. Klessen, Mordecai Mark Mac Low

Research output: Contribution to journalArticle

140 Citations (Scopus)

Abstract

We study the effect of varying the equation of state on the formation of stellar clusters in turbulent molecular clouds using three-dimensional, smoothed particle hydrodynamics simulations. Our results show that the equation of state helps determine how strongly self-gravitating gas fragments. The degree of fragmentation decreases with increasing polytropic exponent γ in the range 0.2 < γ < 1.4, although the total amount of mass accreted onto collapsed fragments appears to remain roughly constant through that range. Low values of γ are expected to lead to the formation of dense clusters of low-mass stars, while γ > 1 probably results in the formation of isolated and massive stars. Fragmentation and collapse ceases entirely for γ > 1.4, as expected from analytic arguments. The mass spectrum of overdense gas clumps is roughly lognormal for now-self-gravitating turbulent gas, but changes to a power law under the action of gravity. The spectrum of collapsed cores, on the other hand, remains lognormal for γ ≤ 1 but flattens markedly for γ > 1. The density probability function approaches lognormal, with widths that decrease with increasing γ. Primordial gas may have effective γ > 1, in which case these results could help explain why models of the formation of the first stars tend to produce isolated, massive objects.

Original languageEnglish (US)
Pages (from-to)975-985
Number of pages11
JournalAstrophysical Journal
Volume592
Issue number2 I
DOIs
StatePublished - Aug 1 2003

Fingerprint

molecular clouds
equation of state
equations of state
gases
gas
fragmentation
stars
clumps
probability density function
probability density functions
massive stars
mass spectra
power law
hydrodynamics
fragments
exponents
gravity
gravitation
effect
simulation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Li, Yuexing ; Klessen, Ralf S. ; Mac Low, Mordecai Mark. / The formation of stellar clusters in turbulent molecular clouds : Effects of the equation of state. In: Astrophysical Journal. 2003 ; Vol. 592, No. 2 I. pp. 975-985.
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The formation of stellar clusters in turbulent molecular clouds : Effects of the equation of state. / Li, Yuexing; Klessen, Ralf S.; Mac Low, Mordecai Mark.

In: Astrophysical Journal, Vol. 592, No. 2 I, 01.08.2003, p. 975-985.

Research output: Contribution to journalArticle

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