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Researchers Find That Bright Nearby Double Star Fomalhaut Is Actually A Triple

October 8, 2013 Leave a comment

The nearby star system Fomalhaut – of special interest for its unusual exoplanet and dusty debris disk – has been discovered to be not just a double star, as astronomers had thought, but one of the widest triple stars known.

In a paper recently accepted for publication in the Astronomical Journal and posted today to the preprint server arXiv, researchers show that a previously known smaller star in its vicinity is also part of the Fomalhaut system.

Eric Mamajek, associate professor of physics and astronomy at the University of Rochester, and his collaborators found the triple nature of the star system through a bit of detective work. “I noticed this third star a couple of years ago when I was plotting the motions of stars in the vicinity of Fomalhaut for another study,” Mamajek said. “However I needed to collect more data and gather a team of co-authors with different observations to test whether the star’s properties are consistent with being a third member of the Fomalhaut system.”

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ALMA Discovers Large “Hot” Cocoon Around A Small Baby Star

October 8, 2013 Leave a comment

Artist impression. Credit: NAOJ

Artist impression. Credit: NAOJ

A large hot molecular cloud around a very young star was discovered by ALMA. This hot cloud is about ten times larger than those found around typical solar-mass baby stars, which indicates that the star formation process has more diversity than ever thought. This result was published in the Astrophysical Journal Letters on September 20th, 2013.

Stars are formed in very cold (-260 degrees Celsius) gas and dust clouds. Infrared Dark Clouds (IRDC) are dense regions of such clouds, and thought that in which clusters of stars are formed. Since most of stars are born as members of star clusters, investigating IRDCs has a crucial role in comprehensive understanding the star formation process.

A baby star is surrounded by the natal gas and dust cloud, and the cloud is warmed up from its center. Temperature of the central part of some, but not all, of such clouds reaches as high as -160 degrees Celsius. Astronomers call those clouds as “hot core” – it may not be hot on the Earth, but is hot enough for a cosmic cloud. Inside hot cores, various molecules, originally trapped in the ice mantle around dust particles, are sublimated. Organic molecules such as methanol (CH3OH), ethyl cyanide (CH3CH2CN), and methyl formate (HCOOCH3) are abundant in hot cores.

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