ExploraTour: A Peek into the Lives of the Stars
The Hubble Space Telescope's View of Star Birth.
This is a dust cloud in the Eagle Nebula (M16) photographed by the Hubble Space Telescope. This dark smoky-looking structure is a column of cool interstellar gas and dust where new stars are being formed.
This cloud was originally much bigger. What we are viewing is the densest part of the cloud that has survived being evaporated by the ultraviolet radiation striking it from nearby young hot stars. Even now you can see streamers of gas boiling away from the main cloud.
Buried deep in the main cloud are denser pockets or globules of gas that are uncovered as the main cloud is evaporated. These globules are called "Evaporating Gaseous Globules" or EGGs for short.
Inside some of these EGGs are protostars (objects that are on their way to becoming stars). If the dust cloud evaporates away from around the EGG before the protostar has evolved into a star, then the protostar may stop growing because it can no longer draw on the cloud for material. In this case, a star will never form and the protostar will become a brown dwarf.
If the protostar survives to become a star, ultraviolet radiation from the new star will help to evaporate the EGG from within.
As the EEG evaporates, a new star emerges into view.