Seeking stars among the clouds
Computer simulation of star formation in a turbulent gas cloud.
An international team of astronomers has developed a new way to reconstruct an interstellar cloud’s three-dimensional structure, to estimate how many new stars the cloud is likely to form.
The results, published in the journal Science, mean that current theories of star formation can be accurately tested.
Led by astronomers from the Max Planck Institute for Astronomy in Heidelberg, Germany, and Monash, the team developed simplified models and numerical simulations of three-dimensional structures of molecular clouds, and compared them to images of real gas and dust clouds in the Milky Way.
Previous observations were limited to information contained in two-dimensional structure of clouds. This new technique allowed the team to partially reconstruct the actual three-dimensional structure of interstellar clouds. It means that for the first time astronomers will be able to directly test star formation theories.
Dr Christoph Federrath of the School of Mathematical Sciences, who provided numerical simulations to test the new technique, said it could potentially tackle one of the greatest unanswered questions of astrophysics.
“We finally have the tools to take a picture of a cloud and predict how many stars we can expect the cloud to form,” Dr Federrath said.
Focusing on clouds within a distance of 1500 light years from Earth, the team compared their reconstruction with direct observations of how many new stars had recently formed in these clouds. In this way, they were able to identify a "critical density" of 5000 hydrogen molecules per cubic centimetre, and showed that only regions exceeding this critical density can collapse to form stars.
The discovery will inform ongoing work to estimate the number and mass of stars that will form in more distant molecular clouds, potentially resulting in a map of star births within our home galaxy.
Read the rest of the article 'Recipe for star formation discovered' at the Monash News site.