The results of a next-to-leading order calculation of heavy quark productio
n in longitudinally polarized photon-nucleon collisions are presented. At c
.m. energy root S = 10 GeV, for gamma + p --> c + X, cross sections differe
ntial in the transverse momentum and rapidity of the charmed quark c and th
e corresponding asymmetries are presented; also, as functions of root S, in
tegrated cross sections, K-factors and the corresponding asymmetries an giv
en. Errors in the asymmetries are estimated and the possibility to distingu
ish between three scenarios differing essentially in the polarized gluon di
stribution is discussed. (C) 2000 Elsevier Science B.V. All rights reserved
.