Abstract
Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass from the surrounding cloud material. This process is investigated, using numerical models of molecular cloud dynamics. Molecular cloud regions without turbulent driving sources, or where turbulence is driven on large scales, exhibit rapid and efficient star formation in a clustered mode, whereas interstellar turbulence that carries most energy on small scales results in isolated star formation with low efficiency. The clump mass spectrum of shock-generated density fluctuations in pure hydrodynamic, supersonic turbulence is not well fit by a power law, and it is too steep at the high-mass end to be in agreement with the observational data. When gravity is included in the turbulence models, local collapse occurs, and the spectrum extends towards larger masses as clumps merge together, a power-law description dN/dM ∝ M ν becomes possible with slope ν ≲ − 2. In the case of pure gravitational contraction, i.e. in regions without turbulent support, the clump mass spectrum is shallower with ν ≈ − 3/2. The mass spectrum of protostellar cores in regions without turbulent support and where turbulence is replenished on large-scales, however, is well described by a log-normal or by multiple power laws, similar to the stellar IMF at low and intermediate masses. In the case of small-scale turbulence, the core mass spectrum is too flat compared to the IMF for all masses.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Adams, F. C., Myers, P. C. 2001, ApJ, in press (astro-ph/0102039)
Bergin, E. A., Goldsmith, P. F., Snell, R. L., Langer, W. D. 1997, ApJ, 428, 285
Elmegreen, B. G. 1993, ApJ, 419, L29
Heitsch, F., Mac Low, M.-M., Klessen, R. S. 2001, ApJ, 547, 280
Klessen, R. S. 2001, ApJ, 550, L77
Klessen, R. S., Burkert, A. 2000, ApJS, 128, 287
Klessen, R. S., Burkert, A. 2001, ApJ, 549, 386
Klessen, R. S., Heitsch, F., Mac Low, M.-M. 2000, ApJ, 535, 887
Lada, E., 1992, ApJ, 393, L25
Mac Low, M.-M., 1999, ApJ, 524, 169
Mac Low, M.-M., Klessen, R. S., Burkert, A., Smith, M. D. 1998, PRL, 80, 2754
Padoan, P. 1995, MNRAS, 277, 337
Padoan, P., Nordlund, A. 2001, ApJ, submitted (astro-ph/0011465)
Zinnecker, H. 1984, MNRAS, 210, 43
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2002 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Klessen, R.S. (2002). Mass Spectra from Turbulent Fragmentation. In: Alves, J.F., McCaughrean, M.J. (eds) The Origins of Stars and Planets: The VLT View. ESO Astrophysics Symposia. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-40277-1_7
Download citation
DOI: https://doi.org/10.1007/978-3-662-40277-1_7
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-662-39255-3
Online ISBN: 978-3-662-40277-1
eBook Packages: Springer Book Archive