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Violent Outbursts
03.19.04
 
Every 50 years or so, a massive star in our galaxy blows itself apart so violently that it burns as bright as ten billion suns.

This intense explosion, called a supernova, is one of the most violent events in the universe. The force of the explosion generates a blinding flash of radiation, as well as shock waves similar to sonic booms.

NASA's Chandra X-ray Observatory, launched in 1999, is the most sophisticated X-ray observatory built to date. Astronomers are using Chandra to learn more about supernovas, including what leads up to the catastrophic explosion and what happens afterward.

Image depicting how a neutron star and supernova remnant are born.Image to right: A three-frame example of how a neutron star and supernova remnant are born. In the first frame, the core of a red giant star implodes. The resulting explosion is depicted in the second frame. The supernova remnant and neutron star that remain are shown in the final frame. Click image for full size version.
Credit: NASA/Chandra X-ray Center/
Penn State University


When the nuclear power source at the core of a star is used up, the core collapses. A black hole or a neutron star -- the dense ball of neutrons that remains -- forms less than a second later. As matter crashes inward, temperatures rise to billions of degrees Celsius. Within hours, a catastrophic explosion blows away everything except the central neutron star. A thermonuclear shock wave races through the expanding wreckage, fusing lighter elements into heavier ones and producing a brilliant visual outburst.

The matter thrown off by the explosion plows through the surrounding gas, producing shock waves that create a shell of multimillion-degree gas and high-energy particles called a supernova remnant. The supernova remnant will produce intense radio and X-radiation for thousands of years.

Chandra can detect these X-rays and help us form a clearer picture of what's left after such a violent event.

In several young supernova remnants, the neutron star spinning at the center gives off pulses of radiation, magnetic fields, and high-energy particles. The result is a magnetized bubble of high-energy particles with radiation that may glow brightly for more than a thousand years. Eventually, the supernova remnant will break up and disappear.
This image shows the relationship between a black hole and a supernova remnant.
Image to left: This Chandra X-ray image shows the relationship between the black hole Sagittarius A* (denoted with an asterisk because it is a point source that emits radio waves) and the supernova remnant Sagittarius A East. Both are located in the center of our galaxy. For the first time, astronomers separated the supernova remnant from other complex structures in the same region.
Credit: NASA/Penn State University


Supernovas heat the interstellar gas, leave behind heavy elements, and trigger the collapse of giant clouds of cool dust and gas to form a new generation of stars. It is probable that a supernova led to the formation of our solar system some five billion years ago and provided the chemical elements necessary for life on Earth.

The cloud that collapsed to form the Sun and its planets was composed mostly of hydrogen, but it was enriched with elements like carbon, nitrogen, oxygen and iron. These heavier elements are created deep inside massive stars, and that's where they would stay if not for supernova explosions.

Chandra continues to provide key information for astronomers compiling detailed maps of supernova remnants. These maps show the differences in temperature, energy, and the quantity and location of elements. But perhaps most breathtaking are the images Chandra captures. The peaceful swirls of color we see in supernova remnants contradict the violent outbursts that created them.

View Chandra images of supernovas and supernova remnants at:
http://chandra.harvard.edu/photo/category/snr.html
 
 
Anna Heiney, KSC Staff Writer
Chandra X-ray Center and NASA's John F. Kennedy Space Center