Gliese 710.

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A view of a small part of the sky as if you were staring at a star (centre) approaching nearly head on, and then as it passes by and away again. The motion can be likened to what an observer standing beside a road would see looking at an approaching car, and then swinging around to continue to follow it as it moves away. As a result, the objects in the background – in this case distant stars – become blurred as you move quickly to maintain a visual on the passing object. The focus of this animation is the star known as Gliese 710. It will have a close encounter with our Sun in 1.3 million years, passing within the Oort Cloud reservoir of comets in the outskirts of our Solar System. The star is predicted to pass within about 2.3 trillion kilometres, the equivalent of about 16 000 Earth–Sun distances. The star’s motion is set against a background of other moving stars and the visualisation covers, very quickly, the timeframe from about 1.1–1.5 million years in the future. The size of...

Cas A Supernova Remnant in X-Rays

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The complex shell of a star seen to explode 300 years ago is helping astronomers to understand how that star exploded. 
The above recently released image of supernova remnant Cassiopeia A (Cas A) shows unprecedented detail in three X-ray colors. 
The relationship between brightness, color, and position of material in the image indicates where in the star this material was just before the explosion. Bright knots on the left, for example, contain little iron, and so are hypothesized to originated from a higher layer than outer red filaments, which are iron rich. 
The blue region on the right is seen through absorbing dust, and so appears depleted of low-energy X-rays. It takes light ten years to cross the gas shell of the Cas A supernova remnant, which is 10,000 light-years distant. Most of the elements that make people and planets were produced in supernova explosions.
John Hughes et al. (Rutgers), NASA/CXC/SAO
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