Gravitational interactions in very young high-density stellar clusters can to some degree
change the angular momentum in the circumstellar discs surrounding initially the majority of stars.
However, for most stars the cluster environment alters the angular momentum
only slightly. For example, in simulations of the Orion Nebula cluster (ONC) encounters reduce
the angular momentum of the discs on average at most by 3-5% and in the higher
density region of the Trapezium
by 15-20% - still a minor loss process.
However, in this paper it is demonstrated that the situation is very different if one considers
high-mass stars (M(star)>10 M(solar)) only.
Assuming an age of 2 Myr for the ONC, their discs have on average a 50-90% lower angular momentum
than primordially. This enormous loss in angular momentum in the disc should
result in an equivalent increase in accretion, implying that the cluster
environment boosts accretion for high-mass stars, thus
making them even more massive.