## 5. Clues on the nature of the extra-mixing process on the rgbThe results described previously were obtained using observational
constraints only, and did not rely on any special prescription for the
extra-mixing. We can nevertheless check whether the value we get for
is consistent with what is expected in a very
simplified rotation framework. Let us follow the suggestion by Huppert
& Spiegel (1977) according to which meridional currents can
penetrate into a region with a stable gradient of molecular weight
within a scale height given by , where r is the
local radius, is the angular rotation velocity,
and the buoyancy frequency due to the
For each of our 3 models, we computed for a
stellar rotation velocity of 2.5 km sec However, we have to be cautious in our conclusions. Indeed,
is derived here in a simplified framework.
Complete computations with rotation-induced mixing have to be
performed. The transport of chemicals and angular momentum should be
treated simultaneously to properly handle the development of
© European Southern Observatory (ESO) 1998 Online publication: March 10, 1998 |