Page "Open cluster" Paragraph 16

As only 30 to 40 per cent of the gas in the cloud core forms stars, the process of residual gas expulsion is highly damaging to the star formation process.

All clusters thus suffer significant infant weight loss, while a large fraction undergo infant mortality.

At this point, the formation of an open cluster will depend on whether the newly formed stars are gravitationally bound to each other ; otherwise an unbound stellar association will result.

Even when a cluster such as the Pleiades does form, it may only hold on to a third of the original stars, with the remainder becoming unbound once the gas is expelled.

The young stars so released from their natal cluster become part of the Galactic field population.