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Vampire Star Reveals its Secrets

December 7, 2011 Leave a comment

Credit: ESO/PIONIER/IPAG

Credit: ESO/PIONIER/IPAG

Astronomers have obtained the best images ever of a star that has lost most of its material to a vampire companion. By combining the light captured by four telescopes at ESO’s Paranal Observatory they created a virtual telescope 130 metres across with vision 50 times sharper than the NASA/ESA Hubble Space Telescope. Surprisingly, the new results show that the transfer of mass from one star to the other in this double system is gentler than expected.

We can now combine light from four VLT telescopes and create super-sharp images much more quickly than before,” says Nicolas Blind (IPAG, Grenoble, France), who is the lead author on the paper presenting the results, “The images are so sharp that we can not only watch the stars orbiting around each other, but also measure the size of the larger of the two stars.

The astronomers observed [1] the unusual system SS Leporis in the constellation of Lepus (The Hare), which contains two stars that circle around each other in 260 days. The stars are separated by only a little more than the distance between the Sun and the Earth, while the largest and coolest of the two stars extends to one quarter of this distance — corresponding roughly to the orbit of Mercury. Because of this closeness, the hot companion has already cannibalised about half of the mass of the larger star.

Full Story: http://www.eso.org/public/news/eso1148/

NASA Mars Rover Finds Mineral Vein Deposited by Water

December 7, 2011 Leave a comment

 Image Credit: NASA/JPL-Caltech/Cornell/ASU

Image Credit: NASA/JPL-Caltech/Cornell/ASU

NASA’s Mars Exploration Rover Opportunity has found bright veins of a mineral, apparently gypsum, deposited by water. Analysis of the vein will help improve understanding of the history of wet environments on Mars.

“This tells a slam-dunk story that water flowed through underground fractures in the rock,” said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for Opportunity. “This stuff is a fairly pure chemical deposit that formed in place right where we see it. That can’t be said for other gypsum seen on Mars or for other water-related minerals Opportunity has found. It’s not uncommon on Earth, but on Mars, it’s the kind of thing that makes geologists jump out of their chairs.”

The latest findings by Opportunity were presented Wednesday at the American Geophysical Union’s conference in San Francisco.

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2011-377

Reborn Active Galactic Nuclei?

December 7, 2011 Leave a comment

Credit: Filho et al. 2011

Credit: Filho et al. 2011

A team of researchers, mainly from Centro de Astrofísica da Universidade do Porto (CAUP), has detected a rare type of active galactic nuclei (AGNs), which have simultaneously characteristics of young and old AGNs. This apparent discrepancy is thought to be due to a recent re-ignition of the central black hole.

The team cross-correlated a catalogue of over 13 thousand clusters with a catalogue at radio frequencies, searching for a link between AGNs and the clusters in which they reside. CAUP astronomer and principal investigator, Mercedes Filho, commented on this chance discovery: “Our initial project aimed to study radio galaxies in clusters. By chance, we found eight radio sources with extended structure (radio jets and lobes) that didn’t show up in the optical images, which we found strange. So we decided to drop the initial project and pursue these strange radio galaxies.”

In order to get more information about these eight objects, further observations in the infrared were made with the VLT (ESO). This allowed the team to detect the host galaxies, where the extended radio structures originated from.

Full Story: http://www.astronews.us/2011-12-07-1930.html