  In this paper we prove a recursion relation between the the one-point genus-0
gravitational descendants of a Stein domain $(M,\partial M)$. This relation is
best described by the degree -2 map $D$ in the linearized contact homology of
$\partial M$, arising from the Bourgeois--Oancea exact sequence between
symplectic homology of $M$ and linearized contact homology of $\partial M$. All
one-point genus-0 gravitational descendants can be reduce to the one-point
Gromov--Witten invariants via iterates of $D$.
