Stars begin their lives as giant, cold clouds of dust and gas in space. As this cloud begins to collapse under its own gravity, a warm clump called a protostar is formed. These early stage stars generate strong magnetic fields as they rotate and many also spit out supersonic jets of gas into space. These protostellar jets normally flow out along the rotation axis of the protostar.
While this much is known, getting decent images of these young stars can be tricky because they are usually surrounded by dust which muddies our view of them. However, researchers can lift the veil on these baby stars by using infrared telescopes instead of optical (visible light) telescopes, which is exactly what a team of researchers from the University of Kent have been doing for the past five years. The survey, named UWISH2, has yielded some truly spectacular images, including the largest number of protostellar jets ever observed.
The UWISH2 team has been surveying an area approximately 1450 times the size of the moon using the UK Infra-Red Telescope in Hawaii. They found jets pouring out of protostars and also planetary nebulae, which are the striking remnants of stars that have ejected a shell of gas. They also imaged the illuminated outlines of huge clouds of dust and gas which are the leftovers of dramatic supernova explosions.
Triggered star formation. The outline of a molecular cloud can be seen, which is illuminated by the ionizing radiation from other stars. Image credit: University of Kent.
Newly discovered planetary nebula, named "Jelly-Fish PN." Image credit: University of Kent.
Based on data gathered so far, the scientists anticipate that around 1,000 jets will be identified by the survey, 90% of which are new discoveries. Furthermore, they expect to identify around 300 planetary nebulae, half of which were previously unknown.
“These discoveries are very exciting,” University of Kent scientist Dr Dirk Froebrich said in a news-release. “We will ultimately have much better statistics, meaning we will be able to investigate the physical mechanisms that determine the jet lengths, as well as their power.”
Froebrich explains that this new information should help us answer some fundamental questions about star formation, such as how these jets are launched and how much energy they spew out into the surrounding interstellar medium.