October 20, 2011
Astronomers Detect Water-Covered Planets
The Herschel Space Observatory has helped astronomers detect water-covered planets like Earth around a young star.
The astronomers used data from Herschel to detect cold water vapor enveloping a dusty disk around the young star.
This is the first time scientists have found evidence of vast quantities of water extending out into the cooler, far reaches of disks where comets take shape.
The more water available in disks for icy comets to form, the greater the chances that large amounts eventually will reach new planets through impacts.
"Our observations of this cold vapor indicate enough water exists in the disk to fill thousands of Earth oceans," astronomer Michiel Hogerheijde of Leiden Observatory in the Netherlands said in a press release.
The star that contains this disk is 10 million years old and lies about 175 light-years away from Earth in the constellation Hydra.
The water haze detected by Hogerheijde and his colleagues is thought to originate from ice-coated grains of dust near the disk's surface.
UV light from the star causes some water molecules to break free of this ice and create a layer of gas with a light signature that Herschel's Heterodyne Instrument for the Far-Infrared can detect.
"These are the most sensitive HIFI observations to date," Paul Goldsmith, NASA project scientist for the Herschel Space Observatory at the agency's Jet Propulsion Laboratory in Pasadena, California, said in a press release. "It is a testament to the instrument builders that such weak signals can be detected."
Astronomers believe TW Hydrae and its icy disk may be representative of many other young star systems, which could help provide scientists insights on how planets with abundant water could form in the universe.
The findings will be published in the Oct. 21 issue of the journal Science.
Image 1: This artist's concept illustrates an icy planet-forming disk around a young star called TW Hydrae, located about 175 light-years away in the Hydra, or Sea Serpent, constellation. Image credit: NASA/JPL-Caltech
Image 2: This graph of data from Herschel shows how the cool water vapor was detected. Image credit: ESA/NASA/JPL-Caltech/Leiden Observatory
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