Debris was part of an asteroid that held the ingredients for habitable planets
© Mark A. Garlick, space-art.co.uk, Univ. of Warwick and Univ. of Cambridge
For the first time, astronomers have discovered the watery building blocks of Earthlike planets whirling around a star outside our solar system.
The star, GD 61, is a white dwarf: a dying star with a gravitational pull strong enough to suck in surrounding asteroids and planets. As GD 61 gobbles up orbiting bodies, it shreds them into a dusty cloud of rubble, says astronomer Jay Farihi of the University of Cambridge.
Using data from the Hubble Space Telescope, Farihi and colleagues analyzed the cloud’s ingredients. They found rock-forming elements such as iron and magnesium, but also a wealth of oxygen. Only one possibility can explain the oxygen, Farihi says: “It has to be water.”
The water and rocky material were part of a large asteroid before GD 61 ripped it to pieces, the researchers report in the Oct. 11 Science.
Just a few waterlogged asteroids smashing into a rocky planet could deliver enough water to fill oceans and lakes. The findings suggest that habitable planets may have once orbited GD 61, a star just 150 light-years away in the constellation Perseus.
J. Farihi, B.T. Gänsicke and D. Koester. Evidence for water in the rocky debris of a disrupted extrasolar minor planet. Science. Vol. 342, October 11, 2013, p. 218. doi: 10.1126/science.1239447.
E. Wayman. Clouds may keep exoplanets cool. Science News Online, July 8, 2013.
A. Grant. Most Earthlike planets yet seen bring Kepler closer to its holy grail. Science News. Vol. 183, May 18, 2013, p. 5.
A. Grant. Meteorite that fell last year contains surprising molecules. Science News. Vol. 184, October 5, 2013, p. 18.
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