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Lunar tandem successfully enters orbit around the Moon
...Ringing in the new year with back-to-back successes, a second NASA science satellite slipped into orbit around the moon Sunday, one day after an identical spacecraft braked into the same polar orbit for a $496 million mission to map the moon's interior by precisely measuring how its gravity affects the trajectories of the twin spacecraft...
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Astronomy Now's year in space
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First “mini-Earth” discovered around Sun-like star
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First direct imaging of a young binary system
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: December 17, 2009


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A team of astronomers have captured the first direct image of a young binary star system using the Coronographic Imager with Adaptive Optics on the Subaru Telescope.

Observed and simulated images of the young binary star SR24 (distance: 520 light years). Image: The graduate University for Advanced Studies & the National Astronomical Observatory of Japan/Chiba University.

The binary star system, SR24, resides 520 light years away in the constellation Ophiuchus. The study, conducted in July 2006, provides important information about how binary stars are born and evolve. In binary systems, two stars orbit around a common centre of mass; the brighter star or massive star is referred to as the primary star and the fainter or less massive star the secondary star. Both star host a disc of material and a third disc may envelope both stars and supply the stars' discs with mass via a connecting spiral arm.

Despite most stars forming in binary or multiple systems, their discs and spiral arms have rarely been directly imaged, that is, until now. The team, lead by astronomers at the National Astronomical Observatory of Japan, captured a high resolution near-infrared image of the discs around each star – the first such image of twin protoplanetary discs around a young stellar object. The images also revealed a long spiral arm extending out from the disc, and a bridge of gas connecting the two discs.

Three-dimensional numerical simulation image of young binary star system. Image: Hosei University.

By inputing various aspects of the observations into supercomputer simulations of accretion and disc formation, the team were able to generate structures similar to those seen in the image. The results suggest that fresh material streams along the spiral arm, replenishing the primary star's disc with a reservoir of gas contained in the disc surrounding both stars. The simulations also suggest that the bridge connecting the stars' discs corresponds to gas flow and a shock wave caused by the collision of gas rotating around the primary and secondary stars.

The findings provide a better understanding of the process of star and planet formation in a binary system by clarifying the role of supporting structures in maintaining the binary system.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
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Hubble Reborn
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3D Universe
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Infinity Rising
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Starry Night
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Exploring Mars
Astronomy Now is pleased to announce the publication of Exploring Mars. The very best images of Mars taken by orbiting spacecraft and NASA's Spirit and Opportunity rovers fill up the 98 glossy pages of this special edition!
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Mars rover poster
This new poster features some of the best pictures from NASA's amazing Mars Exploration Rovers Spirit and Opportunity.
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