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neutronstar
Violent Stellar Winds in an X-ray Binary System
Jeff Benensohn, Don Q. Lamb (University of Chicago), Ronald E. Taam (Northwestern University)
The majority of stars in our Milky Way Galaxy exist in binary or multiple systems. These systems consist of two or more stars that are bound gravitationally to one another. Our Solar System is an example of a gravitationally-bound system, the Sun being massive enough to attract the nearby planets. However, if we consider a binary star system, a logical question to ask is what happens when these two stars evolve? In many cases, one star evolves faster than the other, causing material from the evolving star to expand outward. This material is pulled in by the companion. For massive stars, the stellar remnant left behind will be a black hole or a neutron star. Simultaneously, the companion star is evolving and matter is eventually thrown back onto the stellar remnant. This material is heated to extreme temperatures as it arrives at the super-dense black hole or neutron star, causing it to glow in X-ray wavelengths. Astronomers call these systems X-ray binaries.
Video: 737 kB, MPEG
The simulation
This animation depicts an X-ray binary system consisting of a neutron star and a supergiant star. The neutron star is very dense, about 10 kilometers (6 miles) in diameter with the mass of 1.5 Suns. The supergiant companion star is about 7 times larger and 15 times more massive than our Sun. The neutron star has a massive gravitational pull, causing the winds from the companion star to be violently pulled into the neutron star. The result is a swirling mess of material in the stellar system, demonstrating the harsh environment produced by the strong gravitational force from the neutron star.
Eve Klein
Binary Neutron Star Collision
David Bock (NCSA Visualization and Virtual Environments Group)
Video: 2 MB, MPEG
Neutron stars are the cinders left over from a supernova explosion. At the instant of their creation, half a million Earth masses of matter are crushed into a ball just ten miles across; one teaspoonful of neutron star material weighs five billion tons. In rare instances, two neutron stars can orbit around each other in a binary system, releasing energy in the form of gravitational radiation. After millions of years, they spiral toward each other, moving faster and faster until they produce a crash so violent that the resulting explosion can be seen billions of light years away.
What happens during the collision?
This movie shows the results of a supercomputer simulation of what might happen when two neutron stars in a binary system collide. By the time they hit each other, they're traveling at nearly the speed of light, and orbit each other a thousand times a second. According to the calculations, the two neutron stars merge together in less than a hundredth of a second and release more energy during that time than our Sun would in ten billion years!
Gordon Myers
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