60-Second Science

Stars Do Dance of Possible Death

Two white dwarf stars orbiting each other will collide in 900,000 years, possibly annihilating both. Steve Mirsky reports

You could think of it as the real dancing with the stars. Two white dwarf 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. [Warren Brown et al., "A 12 minute Orbital Period Detached White Dwarf Eclipsing Binary"]

One of the stars is about the size of Earth, but has more than half the mass of the sun. A penny as dense 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.

Astronomers estimate that the partners will collide in about 900,000 years. At that time, they could form a stable binary star, or merge 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.

—Steve Mirsky

[The above text is a transcript of this podcast.]

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