Gravity plays larger role in star formation than previously thought

January 1st, 2009 - 2:52 pm ICT by ANI  

Washington, Jan 1 (ANI): New computer visualization technology developed by researchers at Harvard University has helped astrophysicists understand that gravity plays a larger role than previously thought in deep spaces vast, star-forming molecular clouds.

The work was led by Astronomy Professor Alyssa Goodman of Harvards Faculty of Arts and Sciences, the Harvard-Smithsonian Center for Astrophysics, and the Initiative in Innovative Computing (IIC).

Goodman and colleagues used the IIC technology to examine reams of astronomical data collected on a structure known as a giant molecular cloud.

The team took advantage of tools developed by the IICs ongoing Astronomical Medicine (A-M) project, which uses technology devised for medical imaging on astronomical research.

To visualize the molecular cloud in three dimensions, it used Astronomical Medicines 3-D Slicer program, originally devised to analyze medical images.

The key advance, however, is a new computer algorithm a set of instructions on how to handle data similar to a computer program or model.

The algorithm, developed by Rosolowsky, outputs results in a dendrogram, which is a treelike representation of data.

From the dendrogram, researchers were able to create 3-D displays of the data that they could then rotate and examine from many different directions.

The simulations are the only way that astronomers can watch what happens over the millions of years it takes to form a star.

Past models of star formation in these clouds assumed that since gravity is a weak force over large distances, its effects are negligible in these clouds until the hydrogen atoms are very close together.

According to Jens Kauffmann of the IIC and the Harvard-Smithsonian Center for Astrophysics, these popular models assume that most of the changes in the clouds come from turbulence and that it is only after turbulence pushes molecules close enough that gravity comes into play.

Once denser groupings of molecules are formed and gravity becomes a factor, they attract more and more particles until either something disrupts them or they have enough mass to collapse and form a star.

But, it is the process up to the point where the dense groupings form that Goodman and colleagues examined.

Their analysis shows that, rather than turbulence being the only significant force pushing these gas molecules around, their gravitational influence on each other is also significant.

That finding means that existing models, which leave gravity out until very dense clumps have formed, would over-predict the rate of star formation in these clouds. (ANI)

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