Twirling Timebomb
Our galaxy contains some oddball stars. Consider the binary systems known as AM CVn stars. One star is a white dwarf -- the dense "corpse" of a star that was once like the Sun. The white dwarf is pulling in gas from its companion -- a star that may also be a white dwarf, but with a surrounding layer of helium.
One example is known as CP Eridani. Its stars are quite close together, so they orbit each other once every 28 minutes. A team led by Villanova astronomer Edward Sion recently studied the system with Hubble Space Telescope. The team was able to view the surface of the white dwarf -- something that had never been done before.
In the next decade, astronomers may learn more about these systems by measuring their "gravitational waves" -- tiny ripples in space-time. No one has detected these waves yet. But an orbiting observatory should be sensitive enough to detect the waves from AM CVn stars and many other sources.
The extra information from gravitational waves should provide a clearer picture of how these systems work. They'll tell astronomers the masses of the individual stars, how far apart they are, and more.
These measurements are important because the white dwarfs may explode. Astronomers use these types of explosions to measure the size of the universe, and how fast it's expanding. So anything that helps astronomers understand how the stars work can also help them deciper the fate of the universe.
Script by Damond Benningfield, Copyright 2006
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
|
Contact | About | Friends of McDonald | Sign up for Sky Tips
