One of the most powerful supercomputers on Earth has simulated the interiors of low mass stars, helping scientists understand their evolution. As these stars exhaust their hydrogen fuel, they eject helium into their surrounding neighbourhood. But the quantities of this ejected helium didn’t match observations by telescopes. This new simulation shows that stars can actually destroy some of this helium inside the star, instead of ejecting it into space.
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Dark Nebula Slithers Across the Sky
This Spitzer photograph contains several nebulae located in the galactic plane of the Milky Way. The dark, snake-like nebula at the upper left contains dozens of huge newborn stars, some with 50 times the mass of our Sun. The red sphere in the image is a supernova remnant. Before it exploded, the central star probably played a role in the creation of the dark nebulae in the region.
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Echos of Light
The strange variable star V838 Monocerotis flared up nearly 5 years ago, and astronomers have been trying to figure out what’s going on ever since. As the light from the flare up propagates out from the star, it illuminates the surrounding cloud of dust. This light reflects off the dust, and we see this echo here on Earth. This latest photograph from the Hubble Space Telescope shows the changes that have happened over the last year. One interesting feature are the whorls and eddies in the dust, which could be caused by powerful magnetic fields.
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Stellar Explosion Has Many Layers
A new photograph from the Spitzer Space Telescope shows how supernova remnant Cassiopeia A evolved over time. The original star contained 15 to 20 times the mass of our Sun, and was made up of concentric shells of elements. The lightest elements, like hydrogen, were in the outermost shell, while the heaviest elements sunk to the centre. The shells of exploded material match up quite well with the original layers in the star before it detonated as a supernova.
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Baby Galaxies Weighed by Spitzer
Astronomers have discovered two of the most distant galaxies ever seen, when the Universe was only 700 million years old. The galaxies were first discovered as part of the Hubble Space Telescope’s Deep Field Survey, which looked into the distant Universe. Astronomers then did follow-on observations with the Spitzer Space Telescope to confirm their distance and age. The galaxies are thought to be between 50-300 million years old, and have only 1% of the mass of our own Milky Way.
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Young Star Grows Up Quickly
New images from the Japanese Subaru telescope show how a nearby young star ended its infancy rapidly. The star, called HD 141569A, has a hole in the disc of gas and dust surrounding it. Astronomers think that the star rapidly ionized its surrounding gas, and then pushed it away with its intense solar radiation. The gap is located about the same distance from the star as Saturn’s orbit, and it lends additional evidence to theories about how discs of material evolve around young stars.
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Nearly a Thousand Years After the Death of a Star
In 1054 A.D., Chinese astronomers recorded the temporary brightening of a star in the constellation Taurus. Nearly 1000 years later, we look in the same region and see the exploded remnants of a dead star: the Crab Nebula. This composite photograph of the Crab Nebula was made by merging images from Hubble, the Chandra X-Ray Observatory, and the Spitzer Space Telescope. It shows only a hail of high-energy particles and expanding debris cloud that once was a massive star.
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Globular Clusters Sort their Stars
Globular clusters are regions of space where stars are densely packed together – 10,000 times more dense than our local stellar neighbourhood. New evidence from the Hubble Space Telescope has shown that globular clusters will sort out themselves out, hoarding more massive stars in the centre, and pushing the less massive stars out to the edges. Hubble captured images of globular cluster 47 Tucanae for nearly 7 years, allowing astronomers to carefully plot the positions of stars moving in the cluster, and then calculate how close they were to the centre.
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Brown Dwarf Companion Seen Directly
Astronomers have directly imaged a brown dwarf companion to the star HD 3651. This star is already known to host an extrasolar planet – less massive than Saturn, but sitting within the orbit of Mercury. HD 3651 is slightly less massive than the Sun, and is located 36 light-years away in the constellation Pisces. The brown dwarf, or HD 3651B, is probably between 20 and 60 Jovian masses, and has a temperature between 500 and 600 degrees Celsius.
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Another Galaxy Smashed Through Andromeda 200 Million Years Ago
Astronomers have gathered evidence that the Andromeda Galaxy collided with dwarf galaxy M32 about 200 million years ago. The evidence was seen by NASA’s Spitzer Space Telescope, which measured the distribution of gas rings in the galaxy’s disk. These dust rings allowed astronomers to calculate when M32 smashed through Andromeda’s galactic plane, like tracing ripples in a pond.
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