Advanced

On the numerical treatment and dependence of thermohaline mixing in red giants

Lattanzio, J. C.; Siess, L.; Church, Ross LU ; Angelou, G.; Stancliffe, R. J.; Doherty, C. L.; Stephen, T. and Campbell, S. W. (2015) In Monthly Notices of the Royal Astronomical Society 446(3). p.2673-2688
Abstract
In recent years much interest has been shown in the process of thermohaline mixing in red giants. In low- and intermediate-mass stars this mechanism first activates at the position of the bump in the luminosity function, and has been identified as a likely candidate for driving the slow mixing inferred to occur in these stars. One particularly important consequence of this process, which is driven by a molecular weight inversion, is the destruction of lithium. We show that the degree of lithium destruction, or in some cases production, is extremely sensitive to the numerical details of the stellar models. Within the standard 1D diffusion approximation to thermohaline mixing, we find that different evolution codes, with their default... (More)
In recent years much interest has been shown in the process of thermohaline mixing in red giants. In low- and intermediate-mass stars this mechanism first activates at the position of the bump in the luminosity function, and has been identified as a likely candidate for driving the slow mixing inferred to occur in these stars. One particularly important consequence of this process, which is driven by a molecular weight inversion, is the destruction of lithium. We show that the degree of lithium destruction, or in some cases production, is extremely sensitive to the numerical details of the stellar models. Within the standard 1D diffusion approximation to thermohaline mixing, we find that different evolution codes, with their default numerical schemes, can produce lithium abundances that differ from one another by many orders of magnitude. This disagreement is worse for faster mixing. We perform experiments with four independent stellar evolution codes, and derive conditions for the spatial and temporal resolution required for a converged numerical solution. The results are extremely sensitive to the time-steps used. We find that predicted lithium abundances published in the literature until now should be treated with caution. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diffusion-hydrodynamics-instabilities-stars, abundances-stars, evolution-stars, interiors
in
Monthly Notices of the Royal Astronomical Society
volume
446
issue
3
pages
2673 - 2688
publisher
Wiley-Blackwell
external identifiers
  • wos:000350272300037
  • scopus:84984963136
ISSN
1365-2966
DOI
10.1093/mnras/stu2238
language
English
LU publication?
yes
id
13976b9a-d716-48f8-a7ea-f65eb87c7c77 (old id 5303963)
date added to LUP
2015-04-27 11:19:32
date last changed
2017-11-19 03:03:07
@article{13976b9a-d716-48f8-a7ea-f65eb87c7c77,
  abstract     = {In recent years much interest has been shown in the process of thermohaline mixing in red giants. In low- and intermediate-mass stars this mechanism first activates at the position of the bump in the luminosity function, and has been identified as a likely candidate for driving the slow mixing inferred to occur in these stars. One particularly important consequence of this process, which is driven by a molecular weight inversion, is the destruction of lithium. We show that the degree of lithium destruction, or in some cases production, is extremely sensitive to the numerical details of the stellar models. Within the standard 1D diffusion approximation to thermohaline mixing, we find that different evolution codes, with their default numerical schemes, can produce lithium abundances that differ from one another by many orders of magnitude. This disagreement is worse for faster mixing. We perform experiments with four independent stellar evolution codes, and derive conditions for the spatial and temporal resolution required for a converged numerical solution. The results are extremely sensitive to the time-steps used. We find that predicted lithium abundances published in the literature until now should be treated with caution.},
  author       = {Lattanzio, J. C. and Siess, L. and Church, Ross and Angelou, G. and Stancliffe, R. J. and Doherty, C. L. and Stephen, T. and Campbell, S. W.},
  issn         = {1365-2966},
  keyword      = {diffusion-hydrodynamics-instabilities-stars,abundances-stars,evolution-stars,interiors},
  language     = {eng},
  number       = {3},
  pages        = {2673--2688},
  publisher    = {Wiley-Blackwell},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {On the numerical treatment and dependence of thermohaline mixing in red giants},
  url          = {http://dx.doi.org/10.1093/mnras/stu2238},
  volume       = {446},
  year         = {2015},
}