  The Galactic centre (GC) is a crowded environment: observations have revealed
the presence of (molecular, atomic and ionized) gas, of a cusp of late-type
stars, and of ~100 early-type stars, about half of which lying in one or
possibly two discs. In this paper, we study the perturbations exerted on a thin
stellar disc (with outer radius ~0.4 pc) by a molecular cloud that falls
towards the GC and is disrupted by the supermassive black hole (SMBH). The
initial conditions for the stellar disc were drawn from the results of previous
simulations of molecular cloud infall and disruption in the SMBH potential. We
find that most of the gas from the disrupted molecular cloud settles into a
dense and irregular disc surrounding the SMBH. If the gas disc and the stellar
disc are slightly misaligned (~5-20 deg), the precession of the stellar orbits
induced by the gas disc significantly increases the inclinations of the stellar
orbits (by a factor of ~3-5 in 1.5 Myr) with respect to the normal vector to
the disc. Furthermore, the distribution of orbit inclinations becomes
significantly broader. These results might be the clue to explain the broad
distribution of observed inclinations of the early-type stars with respect to
the normal vector of the main disc. We discuss the implications for the
possibility that fresh gas was accreted by the GC after the formation of the
disc(s) of early-type stars.
