Scientists have found, for the first time, evidence of water on a rocky celestial body outside of our solar system.
The study focused on dust and debris found orbiting a white dwarf star about 170 million light years away.
“This planetary graveyard swirling around the embers of its parent star is a rich source of information about its former life,” Boris Gaensicke, a professor of physics at the University of Warwick in the United Kingdom, said. “In these remnants lie chemical clues which point towards a previous existence as a water-rich terrestrial body.”
“Those two ingredients — a rocky surface and water — are key in the hunt for habitable planets outside our solar system so it’s very exciting to find them together for the first time outside our solar system.”
The debris probably came from a planet with a diameter of at least 90 kilometers. The planet may have been much bigger than that, but scientists are limited in their ability to estimate its size by the amount of debris that can now be detected.
Oxygen signatures in the debris indicates that the planet would have been, as a proportion of its mass, about 26 percent water.
Water accounts for about 0.023 percent of Earth’s mass.
Scientists had earlier found evidence of water outside our solar system in gas giants. This discovery is significant because it is the first indication that water may be found on rocky exoplanets.
A possible parallel in our solar system is the dwarf planet Ceres, which has ice buried under its crust.
The star around which the debris is accumulated, GD 61, once hosted a planetary system. It became a white dwarf about 200 million years ago.
The discovery of the GD 61 system planetary remnants is the twelfth known example of planetary fragments circling a white dwarf elsewhere in our galaxy.
Researchers used the Hubble Space Telescope and the large Keck Telescope in Hawaii to make the observations in the study.
The paper can be found here.
Note: A version of this diary also appears at SciencefortheFuture.com.