The formation of stars

The Orion Nebula, M42, contains several dusty discs called 'proplyds' (below). These may be planetary systems under formation.

The Eagle Nebula, M16.

To astronomers and laymen alike the topic of star formation has always been a particularly appealing one. The reason being that important clues about our genesis lie hidden behind the veil of the dusty, and often very beautiful, star forming molecular clouds. Our Earth and the Solar System were born 4.6 billion years ago and our knowledge of the event is sparse. Astronomers turn their eyes to the birth of other stars and stellar systems in neighbouring stellar ‘maternity wards’ and use these as a time machine to see a replay of the events that created our own Solar System.

Inside the Orion Nebula
The large mosaic of 15 Hubble images showing the central part of the Orion complex is one of the most detailed images of a star forming region ever made. It shows a very young star cluster blowing a ‘bubble’ in its remnant parent cloud of glowing gas so that the stars start to be seen in visible light – like the smoke in a forest fire being driven away by the heat.
Hubble’s high resolution has been crucial in the investigation of the dust disks, dubbed proplyds, around the newly born stars in the Orion Nebula. The ‘proplyds’ may very well be young planetary systems in the early phases of their creation. The details that are revealed are better than what has been achieved with ground-based instruments, and thanks to Hubble we have today visual proof that dusty disks around young stars are common.

Peering through dust
Since star birth always seems to take place in dusty environments, Hubble’s infrared capabilities have been a very important factor. The infrared instrument NICMOS can peer through large parts of the dust and reveal the complex processes taking place in the star forming regions. Otherwise invisible close double and multiple stars were discovered, as well as faint substellar brown dwarf companions. With NICMOS and its visual counterpart WFPC2, Hubble has observed giant jets of material spewing out from infant stars surrounded by large disks of dust. A fantastic view into the dramatic first steps in the lives of newly born stars.