60-Second Science

Dead Stars Tell of Rocky Planets

A study presented at the meeting of the American Astronomical Society finds that the debris surrounding white dwarf stars is similar to the content of rocky planets--which means that rocky planets could be common to stars like our sun. Cynthia Graber reports

[The following is an exact transcript of this podcast.]

If we want to learn more about our planet and other planets in the universe, we can get some help from stars that are long dead and gone. That’s what U.C.L.A.’s Michael Jura said at the American Astronomical Society meeting January 5th. His team used observations from NASA’s Spitzer Space Telescope to investigate dead white dwarf stars.

Dust and debris swirl around young stars. The pieces clump together to form asteroids and bigger planets. When a star like our sun finally dies, it blows itself up, bright red. Then it shrinks down into a skeleton of its former self—a white dwarf. The gravitational pull of these white dwarfs can attract nearby asteroids that then get pulverized.

Eight different white dwarf systems were examined. In the surrounding asteroid dust, there was a mineral similar to olivine, which is common here on Earth. And there wasn’t much carbon, also similar to the make-up of asteroids and rocky planets in our own solar system. The results suggest that the same materials that make up Earth and our solar system's other rocky bodies could be common in the universe. As could be rocky planets themselves. An insight for which we can thank dead stars.

—Cynthia Graber 

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