Gas cloud may be precursor to massive star


POSTED: Sunday, July 26, 2009

A team led by University of Hawaii astronomer Jonathan Swift has discovered for the first time what may be a birthing place for a massive star or stars in a cosmic cloud.

Using the Submillimeter Array on Mauna Kea, the astronomers found a massive, tranquil object in a cloud of molecular gas 23,000 light years away in the Aquila Rift in the Milky Way.

Swift said it's likely to be “;the direct progenitor of a massive star or stars.”; If so, it would be the first time scientists have been able to see such a region before massive stars form, he said.

A post-doctoral researcher in the UH Institute for Astronomy, Swift reported the findings at an American Astronomical Society meeting in Pasadena, Calif., in a UH news release and by e-mail.

He said the core of gas is equal to the mass of 120 suns.

It is likely to evolve into one or more massive stars because of a large amount of cold dense gas that's less than 18 degrees above absolute zero, he said. Stars with a mass of more than eight times that of the sun are much rarer than sun-like stars but have “;short, spectacular lives”; because of extreme radiation, he reported.

“;Massive stars die violently in supernova events so luminous that for short times they can outshine entire galaxies. It is within these death throes that elements heavier than iron are formed, including gold and silver.”;

General knowledge of massive stars has been critical in understanding the evolution of the cosmos, but they are rare and difficult to understand because they quickly destroy their environments, Swift said.

However, the team has come across a second core with 70 solar masses and a slightly smaller size, he said.

Collaborators at Harvard's Center for Astrophysics are leading surveys to search for more objects with the Submillimeter Array, which combines radio signals from two or more of eight antennas to produce extremely high resolution images of wavelengths longer than the far-infrared.