Influence of thermohaline convection on diffusion-induced iron accumulation in A stars

Abstract

Atomic diffusion may lead to heavy element accumulation inside stars in certain specific layers. Iron accumulation in the Z-bump opacity region has been invoked by several authors to quantitatively account for abundance anomalies observed in some stars, or to account for stellar oscillations through the induced $\kappa$-mechanism. These authors however never took into account the fact that such an accumulation creates an inverse $\mu$-gradient, unstable for thermohaline convection. Here, we present results for A-F stars, where abundance variations are computed with and without this process. We show that iron accumulation is still present when thermohaline convection is taken into account, but much reduced compared to when this physical process is neglected. The consequences of thermohaline convection for A-type stars as well as for other types of stars are presented

19 pages, 8 figures Accepted for publication in Astrophysical Journal, August 4, 2009

References in corpus (7)

• Instability strips of SPB and beta Cephei stars: the effect of the updated OP opacities and of the metal mixture
• Thermohaline mixing and gravitational settling in carbon-enhanced metal-poor stars
• CS22964-161: A Double-Lined Carbon- and s-Process-Enhanced Metal-Poor Binary Star
• Inhibition of thermohaline mixing by a magnetic field in Ap star descendants: Implications for the Galactic evolution of 3He
• Light element abundances in carbon-enhanced metal-poor stars
• Instability strips of main sequence B stars: a parametric study of iron enhancement
• The convective envelope in gamma Doradus stars: theoretical uncertainties

Cited by in corpus (37)

• Thermohaline instability and rotation-induced mixing. I - Low- and intermediate-mass solar metallicity stars up to the end of the AGB
• First Kepler results on compact pulsators I. Survey target selection and the first pulsators
• Metal-rich accretion and thermohaline instabilities in exoplanets-host stars: consequences on the light elements abundances
• Slowing down atomic diffusion in subdwarf B stars: mass loss or turbulence?
• Horizontal Branch evolution, metallicity and sdB stars
• AmFm and lithium gap stars: Stellar evolution models with mass loss
• Impacts of radiative accelerations on solar-like oscillating main-sequence stars
• First Kepler results on compact pulsators VIII: Mode identifications via period spacings in $g-$mode pulsating Subdwarf B stars
• The Gaia-ESO survey: 3D NLTE abundances in the open cluster NGC 2420 suggest atomic diffusion and turbulent mixing at the origin of chemical abundance variations
• Excitation of gravity waves by fingering convection, and the formation of compositional staircases in stellar interiors
• Spots on Am stars
• The new Toulouse-Geneva Stellar Evolution Code including radiative accelerations of heavy elements
• Hydrodynamical instabilities induced by atomic diffusion in A stars and their consequences
• A search for non-pulsating, chemically normal stars in the $\delta$ Scuti instability strip using Kepler data
• Asteroseismic modeling of gravity modes in slowly rotating A/F stars with radiative levitation
• 2D or not 2D: the effect of dimensionality on the dynamics of fingering convection at low Prandtl number
• Precise Modeling of the Exoplanet Host Star and CoRoT Main Target HD 52265
• Fingering Convection in Red Giants Revisited
• Fingering convection induced by atomic diffusion in stars: 3D numerical computations and applications to stellar models
• Primordial nucleosynthesis with varying fundamental constants: Solutions to the Lithium problem and the Deuterium discrepancy
• Abundance anomalies in pre-main-sequence stars: Stellar evolution models with mass loss
• Predictions for gravity-mode periods and surface abundances in intermediate-mass dwarfs from shear mixing and radiative levitation
• Importance of fingering convection for accreting white dwarfs in the framework of full evolutionary calculations: the case of the hydrogen-rich white dwarfs GD133 and G29-38
• The blue-edge problem of the V1093 Her instability strip revisited using evolutionary models with atomic diffusion
• Chemically peculiar A and F stars with enhanced s-process and iron-peak elements: stellar radiative acceleration at work
• The interaction between shear and fingering (thermohaline) convection
• Asteroseismology of the exoplanet-host F-type star 94 Ceti : impact of atomic diffusion on the stellar parameters
• Stellar models with self-consistent Rosseland opacities
• An improved parametric method for evaluating radiative accelerations in stellar interiors
• Pre-main sequence accretion and the formation of multiple populations in Globular Clusters
• Matter accretion in metal-poor stars down to extremely metal-poor stars and the lithium problem
• Atomic diffusion in solar-like stars with MESA. Comparison with the Montreal/Montpellier and CESTAM stellar evolution codes
• Assessing the processes behind planet engulfment and its imprints
• Glitches in solar-like oscillating F-type stars: Theoretical signature of the base of the convective envelope on the ratios $r_{010}$
• Recent Advances in Modeling Stellar Interiors
• Modelling of the scandium abundance evolution in AmFm stars
• Radiative acceleration calculation methods and abundance anomalies in Am stars