The effect of rotation on fingering convection in stellar interiors

Abstract

We study the effects of rotation on the growth and saturation of the double-diffusive fingering (thermohaline) instability at low Prandtl number. Using direct numerical simulations, we estimate the compositional transport rates as a function of the relevant non-dimensional parameters - the Rossby number, inversely proportional to the rotation rate, and the density ratio which measures the relative thermal and compositional stratifications. Within our explored range of parameters, we generally find rotation to have little effect on vertical transport. However, we also present one exceptional case where a cyclonic large scale vortex (LSV) is observed at low density ratio and fairly low Rossby number. The LSV leads to significant enhancement in the fingering transport rates by concentrating compositionally dense downflows at its core. We argue that the formation of such LSVs could be relevant to solving the missing mixing problem in RGB stars.

16pages, 20 figures, submitted to ApJ

References in corpus (16)

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• Thermohaline mixing: A physical mechanism governing the photospheric composition of low-mass giants
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• Chemical Transport and Spontaneous Layer Formation in Fingering Convection in Astrophysics
• Inhibition of thermohaline mixing by a magnetic field in Ap star descendants: Implications for the Galactic evolution of 3He
• Condensates in rotating turbulent flows
• 3He-Driven Mixing in Low-Mass Red Giants: Convective Instability in Radiative and Adiabatic Limits
• Fingering Convection in Red Giants Revisited
• The effect of rotation on oscillatory double-diffusive convection (semiconvection)
• Impact of domain anisotropy on the inverse cascade in geostrophic turbulent convection
• Inverse cascades and resonant triads in rotating and stratified turbulence
• Why compositional convection cannot explain substellar objects sharp spectral type transitions
• Double-diffusive mixing in stellar interiors in the presence of horizontal gradients
• Rotational mixing in carbon-enhanced metal-poor stars with s-process enrichment

Cited by in corpus (16)

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• Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era
• Polluted White Dwarfs: Mixing Regions and Diffusion Timescales
• Light Elements in the Universe
• Rotating double-diffusive convection in stably stratified planetary cores
• Enhanced mixing in magnetized fingering convection, and implications for RGB stars
• Is Thermohaline Mixing the Full Story? Evidence for Separate Mixing Events near the Red Giant Branch Bump
• The interaction between shear and fingering (thermohaline) convection
• Inferring the velocity of early massive stars from the abundances of extremely metal-poor stars
• An Investigation of Non-Canonical Mixing in Red Giant Stars Using APOGEE 12C/13C Ratios Observed in Open Cluster Stars
• Fingering convection in the stably-stratified layers of planetary cores
• Green Bank Telescope Observations of ${}^3\mathbf{H}{\mathbf{e}}^{+}$: Planetary Nebulae
• Do All Low-Mass Stars Undergo Extra Mixing Processes?
• Compositional Turbulence and Layering in the Gaseous Envelopes of Forming Planets
• Regime transitions of dynamos driven by fingering double-diffusive convection
• Influence of Rotation on Fingering Convection in Planetary Cores