  This paper investigates the spin-up of a mass-accreting star in a close
binary system passing through the first stage of mass exchange in the
Hertzsprung gap. Inside an accreting star, angular momentum is carried by
meridional circulation and shear turbulence. The circulation carries part of
the angular momentum entering the accretor to its surface. The greater the rate
of arrival of angular momentum in the accretor is, the greater this part. It is
assumed that this part of the angular momentum can be removed by the disk
further from the accretor. If the angular momentum in the matter entering the
accretor is more than half the Keplerian value, then the angular momentum
obtained by the accretor during mass exchange stage does not depend on the rate
of arrival of angular momentum. The accretor may have the characteristics of a
Be-star immediately after the end of mass exchange.

Solar and Stellar Astrophysics;High Energy Astrophysical Phenomena