SSS 2011-07-13

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You could think of it as the real dancing with the stars. Two white dwarf¹ stars have been found twirling around each other to make a complete orbit in less than every 13 minutes. And they provide a chance to test ideas about general relativity and gravitational waves. The system is described in a paper accepted by the Astrophysical Journal Letters. 

 

One of the stars is about the size of Earth, but has more than half the mass of the Sun. A penny as dense² as the star would weigh half a ton here. The other star is about 60 times our size and has about half the mass of its companion. 

 

Astronomers³ estimate that the partners will collide in about 900,000 years. At that time, they could form a stable binary⁴ star, or merge⁵ into a single, rapidly spinning white dwarf, or go supernova. In the meantime, they provide a place to look for gravitational waves. Because they're not exchanging mass now, gravitational waves should account for the loss of energy that brings them closer every year. Which for each of them around the other is just a few podcasts long.

 

Thanks for the minute. For Scientific American's 60-Second Science, I'm Steve Mirsky.

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