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Bloêcker, T.; Holweger, H.; Freytag, B.; Herwig, Falk; Ludwig, H.‐G.; Steffen, M.

doi:10.1023/a:1005192804708

Cited by 17 publications

(13 citation statements)

References 12 publications

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“…Since overshooting increases the extension of convective regions, the occurrence of HEFM is in principle favoured. Our overshooting description follows Blöcker et al (1998) and it is modelled as an exponential diffusive process. The diffusion constant of the overshoot region decays exponentially outside the Schwarzschild convective boundary, starting from the value assumed by the convective diffusion coefficient at the convective boundary; the decay length is F times the pressure scale height at the convective boundary.…”

Section: Models Including Overshootingmentioning

confidence: 99%

The surface carbon and nitrogen abundances in models of ultra metal-poor stars

Schlattl

Salaris

Cassisi

et al. 2002

A&A

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Abstract. We investigate whether the observed high number of carbon-and nitrogen-enhanced extremely metal-poor stars could be explained by peculiar evolutionary properties during the core He flash at the tip of the red giant branch. For this purpose we compute a series of detailed stellar models expanding upon our previous work; in particular, we investigate if during the major He flash the penetration of the helium convective zone into the overlying hydrogen-rich layers can produce carbonand nitrogen-rich abundances in agreement with current spectroscopic observations. The dependence of this phenomenon on selected model input parameters, such as initial metallicity and treatment of convection is examined in detail.

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Section: Models Including Overshootingmentioning

confidence: 99%

The surface carbon and nitrogen abundances in models of ultra metal-poor stars

Schlattl

Salaris

Cassisi

et al. 2002

A&A

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“…Nevertheless, a certain level of turbulence resulting, e.g., from instabilities of rotational shear (Goldreich & Schubert 1967) or forcing from the upper convection zone (Blöcker et al 1998) is possible and even necessary to explain rotational coupling between the radiative core and the convective envelope, or the depletion of light elements in solar-type stars.…”

Section: Introductionmentioning

confidence: 99%

Transport of angular momentum and chemical species by anisotropic mixing in stellar radiative interiors

Kitchatinov

Brandenburg

2012

Astron Nachr

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Small levels of turbulence can be present in stellar radiative interiors due to, e.g., the instability of rotational shear. In this paper we estimate turbulent transport coefficients for stably stratified rotating stellar radiation zones. Stable stratification induces strong anisotropy with a very small ratio of radial-to-horizontal turbulence intensities. Angular momentum is transported mainly due to the correlation between azimuthal and radial turbulent motions induced by the Coriolis force. This non-diffusive transport known as the Λ-effect has outward direction in radius and is much more efficient compared to the effect of radial eddy viscosity. Chemical species are transported by small radial diffusion only. This result is confirmed using direct numerical simulations combined with the test-scalar method. As a consequence of the non-diffusive transport of angular momentum, the estimated characteristic time of rotational coupling ( < ∼ 100 Myr) between radiative core and convective envelope in young solar-type stars is much shorter compared to the time-scale of Lithium depletion (∼1 Gyr).

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“…One possibility is overshooting convection (Ahrens et al 1992;Blöcker et al 1999;Schlattl & Weiss 1999) another one is (highly) anisotropic turbulence stabilized by the radial temperature gradient (Zahn 1992;Vincent et al 1996). In both cases the resulting anisotropies are opposing and so is the influence of the basic stellar rotation.…”

Section: Introductionmentioning

confidence: 99%

Rotation-induced lithium depletion of solar-type stars in open stellar clusters

Tschäpe

Rüdiger

2001

A&A

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Abstract.We look for a correlation between Lithium abundance and rotation period in solar-type stars (G0. . . K0). The result is not unambiguous. Stars in young open clusters (IC 2391, IC 2602, IC 4665, α Per) do not show any correlation, in the Pleiades cluster a correlation is present: the faster the rotation the less the Lithium depletion. Moreover, there is statistical evidence, that at least in the Pleiades and in the α Persei cluster the abundance spread at fixed color in cool stars could be due to rotation. The use of the inverse Rossby number instead of the rotation rate does not improve on the Li-rotation correlation.

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Cited by 17 publications

References 12 publications

The surface carbon and nitrogen abundances in models of ultra metal-poor stars

The surface carbon and nitrogen abundances in models of ultra metal-poor stars

Transport of angular momentum and chemical species by anisotropic mixing in stellar radiative interiors

Rotation-induced lithium depletion of solar-type stars in open stellar clusters

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