Theory and numerics: New results on convection in stars

W David Arnett, Casey Meakin, Sumner Starrfield, Frank Timmes, Patrick Young

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

We have begun a new program to improve the treatment of turbulent convection in stars; it features Convection Algorithms Based on Simulations (CABS). We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of the simulations. The procedure is testable and allows systematic improvement. The interpretation of mixing-length theory (MLT) as generally used in astrophysics is incorrect. Direct tests show that the damping associated with the turbulent cascade is that suggested by Kolmogorov [1] (εK≈(u′)3rms/lCZ), where lCZ is the depth of the convection zone. This implies that the mixing-length parameter α is a simple function of depth of the convection zone, and not freely adjustable. Appropriate adjustment of another parameter of MLT, the "geometric factor", can leave solar models almost unchanged, except for their velocity scale. This parameter adjusts the super-adiabatic region just below the photosphere, and represents a crude interpolation function for characterizing 3D hydrodynamic atmospheres.

Original languageEnglish (US)
Title of host publicationAIP Conference Proceedings
Pages287-294
Number of pages8
Volume1001
DOIs
StatePublished - 2008
Event9th Torino Workshop on Evolution and Nucleosynthesis in AGB Stars and the 2nd Perugia Workshop on Nuclear Astrophysics - Perugia, Italy
Duration: Oct 21 2007Oct 27 2007

Other

Other9th Torino Workshop on Evolution and Nucleosynthesis in AGB Stars and the 2nd Perugia Workshop on Nuclear Astrophysics
CountryItaly
CityPerugia
Period10/21/0710/27/07

Fingerprint

convection
stars
cascades
stellar convection
hydrodynamics
simulation
photosphere
closures
interpolation
astrophysics
damping
adjusting
atmospheres

Keywords

  • Hydrodynamics
  • Stars
  • Stellar Evolution
  • Turbulence

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Arnett, W. D., Meakin, C., Starrfield, S., Timmes, F., & Young, P. (2008). Theory and numerics: New results on convection in stars. In AIP Conference Proceedings (Vol. 1001, pp. 287-294) https://doi.org/10.1063/1.2916977

Theory and numerics : New results on convection in stars. / Arnett, W David; Meakin, Casey; Starrfield, Sumner; Timmes, Frank; Young, Patrick.

AIP Conference Proceedings. Vol. 1001 2008. p. 287-294.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Arnett, WD, Meakin, C, Starrfield, S, Timmes, F & Young, P 2008, Theory and numerics: New results on convection in stars. in AIP Conference Proceedings. vol. 1001, pp. 287-294, 9th Torino Workshop on Evolution and Nucleosynthesis in AGB Stars and the 2nd Perugia Workshop on Nuclear Astrophysics, Perugia, Italy, 10/21/07. https://doi.org/10.1063/1.2916977
Arnett WD, Meakin C, Starrfield S, Timmes F, Young P. Theory and numerics: New results on convection in stars. In AIP Conference Proceedings. Vol. 1001. 2008. p. 287-294 https://doi.org/10.1063/1.2916977
Arnett, W David ; Meakin, Casey ; Starrfield, Sumner ; Timmes, Frank ; Young, Patrick. / Theory and numerics : New results on convection in stars. AIP Conference Proceedings. Vol. 1001 2008. pp. 287-294
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