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Stellar Encounters
Joshua E. Barnes (University of Hawaii)
Video: 1 MB, MPEG
Close encounters between stars are very rare. Only a few of the billions of stars in a typical galaxy will ever collide. Nonetheless, encounters between stars can play an interesting role in the formation of exotic star systems. This supercomputer simulation shows what might happen if a small star crashes into a larger one.
When stars collide
The movie shows one star crashing into another star twice its mass. Stars are not solid objects, but are composed of gas that surrounds a small, dense core. When stars collide, their cores spiral into each other, while their gaseous envelopes swirl about. The friction caused by all this motion releases a tremendous amount of heat and energy. This is shown in the movie by the colors in the stars: red regions have high energy while blue regions have low energy.
Gordon Myers
Mass Transfer in Binary Stars
John M. Blondin, Marcedes T. Richards, Michael L. Malinowski (North Carolina State University)
The binary star Algol (Beta Persei) was the first eclipsing variable star ever discovered, and it's still the most famous one. Algol brightens and fades like clockwork every 2.87 days, and its changes are very plain to the unaided eye. The variation in its brightness is caused by one star in the system periodically blocking the other as they orbit. Astronomers have discovered that matter from one star actually flows onto the other star! This supercomputer calculation shows what that matter flow might look like.
Video: 935 kB, MPEG
Stellar distortion
The calculations shown in this visualization demonstrate that, when matter flows from one star in the Algol system to the other, the stars become distorted from their normal spherical shapes. The matter flows through a single critical point between the two stars, called the inner Lagrangian point,
and interacts with the heat and radiation from the stars to form twisted braids, loops and streamers.
Charles Liu
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Ring Around Supernova 1987A
John M. Blondin (North Carolina State University)
One of the most exciting astronomical events of the 20th century occurred in February 1987 when the first naked-eye supernova in centuries appeared in the Large Magellanic Cloud. In the past decade, three rings of glowing matter have developed around the explosion site. Astronomers have shown that the rings are made of material that surrounded the supernova's progenitor star. This visualization shows how that sort of cold, dark material can begin to glow when a supernova blast wave crashes into it.
Video: 462 kB, MPEG
Supernova shock
In the movie, you see a cross-section view of one possible glowing smoke ring.
Imagine the supernova blast wave traveling from left to right; the circle on the right hand side represents a doughnut
of cold gas being hit by the blast wave. The calculation shows that the blast wave plows into the ring like a blowtorch; much of the gas is blown away, while the rest is set aglow by the blast wave's powerful kinetic energy. The gas reaches temperatures in the millions of degrees, hot enough to glow in X-rays as well as ultraviolet, visible, and infrared light.
Charles Liu
