Meridional circulation and the lithium abundance gap in F stars

Journal Article · Tue Nov 01 04:00:00 EST 1988 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/166875· OSTI ID:6535262

Charbonneau, P; Michaud, G

The effect of meridional circulation on the time evolution of superficial abundances of helium, lithium, and beryllium in F stars is calculated in detail. It is shown that, as long as the presence of convection zones is assumed not to modify global meridional circulation patterns, the maximum equatorial rotational velocity allowing the settling of Li and He decreases rapidly with T(eff), going from 50 km/s at 7250 K to only 5 km/s at 6400 K. It is also shown that, for stars of the age of the Hyades with T(eff) less than 7000 K and rotational velocities larger than about 25 km/s, meridional circulation is rapid enough to bring to the surface matter that originally was deep enough to have been depleted of its Li through nuclear burning. Observational tests are suggested to distinguish between this scenario and the gravitational settling model or turbulent diffusion model. It is shown how the Li/Be ratio varies in the presence of transport by meridional circulation. 48 references.

• Research Organization: Montreal Universite, Montreal (Canada)
• OSTI ID: 6535262
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 334; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ALKALI METALS
ALKALINE EARTH METALS
ANGULAR VELOCITY
BERYLLIUM
CHEMICAL COMPOSITION
CONVECTION
ELEMENTS
ENERGY TRANSFER
FLUIDS
GASES
HEAT TRANSFER
HELIUM
LITHIUM
MASS TRANSFER
MATHEMATICAL MODELS
METALS
MOTION
NONMETALS
QUANTITY RATIO
RARE GASES
ROTATION
STAR BURNING
STARS
VELOCITY