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Comet Collisions Every Six Seconds Explain 17-Year-Old Stellar Mystery

November 14, 2012 Leave a comment

Every six seconds, for millions of years, comets have been colliding with one another near a star in the constellation Cetus called 49 CETI, which is visible to the naked eye. Over the past three decades, astronomers have discovered hundreds of dusty disks around stars, but only two — 49 CETI is one — have been found that also have large amounts of gas orbiting them.

Young stars, about a million years old, have a disk of both dust and gas orbiting them, but the gas tends to dissipate within a few million years and almost always within about 10 million years. Yet 49 CETI, which is thought to be considerably older, is still being orbited by a tremendous quantity of gas in the form of carbon monoxide molecules, long after that gas should have dissipated.

“We now believe that 49 CETI is 40 million years old, and the mystery is how in the world can there be this much gas around an otherwise ordinary star that is this old,” said Benjamin Zuckerman, a UCLA professor of physics and astronomy and co-author of the research, which was recently published in the Astrophysical Journal. “This is the oldest star we know of with so much gas.”

Zuckerman and his co-author Inseok Song, a University of Georgia assistant professor of physics and astronomy, propose that the mysterious gas comes from a very massive disk-shaped region around 49 CETI that is similar to the sun’s Kuiper Belt, which lies beyond the orbit of Neptune.

Full Story: http://newsroom.ucla.edu/portal/ucla/comet-collisions-every-six-seconds-240565.aspx

‘Cosmic GDP’ Crashes 97% As Star Formation Slumps

November 14, 2012 Leave a comment

While parts of the world experience economic hardship, a team of Portuguese, UK, Japanese, Italian and Dutch astronomers has found an even bigger slump happening on a cosmic scale. In the largest ever study of its kind, the international team of astronomers has established that the rate of formation of new stars in the Universe is now only 1/30th of its peak and that this decline is only set to continue. The team, led by David Sobral of the University of Leiden in the Netherlands, publish their results in the journal Monthly Notices of the Royal Astronomical Society.

The accepted model for the evolution of the Universe suggests that stars began to form about 13.4 billion years ago, or around three hundred million years after the Big Bang. Many of these first stars are thought to have been monsters by today’s standards, and were probably hundreds of times more massive than our Sun. Such beasts aged very quickly, exhausted their fuel, and exploded as supernovae within a million years or so. Lower mass stars in contrast have much longer lives and last for billions of years.

In the new study, scientists used the UK Infrared Telescope (UKIRT), the Very Large Telescope (VLT) and the Subaru telescope to carry out the most complete survey ever made of star-forming galaxies at different distances, with around ten times the data of any previous effort. With the range of distances, the time taken for the light to reach us means that we see identically selected galaxies at different periods in the history of the universe, so we can really understand how conditions change over time.

Full Story: http://www.ras.org.uk/news-and-press/219-news-2012/2187-cosmic-gdp-crashes-97-as-star-formation-slumps

Once In A Lifetime Experience For theSkyNet Citizen Scientist

November 14, 2012 Leave a comment

Last week the top contributor to citizen science initiative theSkyNet travelled to the heart of the West Australian outback to visit the future site of the Square Kilometre Array (SKA) radio telescope. Mr Kim Hawtin, top contributor to the International Centre for Radio Astronomy Research (ICRAR) project, was awarded this rare opportunity as part of theSkyNet’s first anniversary celebrations in September.

“The key to theSkyNet is having lots of computers connected, with each contributing only a little, but the sum of those computers achieving a lot,” he said. Mr Wheeler said that Mr Hawtin’s contribution has been an important part of theSkyNet’s overall processing capacity.

Full Story: http://www.icrar.org/news/news_items/media-releases/once-in-a-lifetime-experience-for-theskynet-citizen-scientist