Jupiter-like planet discovered by new tech
Astronomers have described the first world discovered by a new instrument designed to capture light reflected off planets outside the solar system.
The "young Jupiter" found by the Gemini Planet Imager (GPI) orbits the star 51 Eridani, 96 light years from Earth, and has an atmosphere rich in methane.
It has roughly twice the mass of Jupiter and may be part of a solar system similar to ours, though less evolved, scientists believe.
To date almost all exoplanets have been detected indirectly, either from gravitational interaction or the dimming of light as a planet passes in front of its star.
But the GPI uses adaptive optics to sharpen a star's image, block out its light, and then search for light reflected off the surface of possible planets.
The GPI was installed last year on the 26ft (eight metre) Gemini South telescope in Chile and has so far identified nearly 100 potential planets.
Writing in the journal Science, astronomers reported their analysis of the first, 51 Eridani b.
The planet was imaged despite being more than three million times fainter than its star, which at just 20 million years old is far younger than the sun.
It looks very like how Jupiter must have appeared in its infancy, said the scientists.
Professor Bruce Macintosh, from Stanford University in the US, said: "Many of the exoplanets astronomers have imaged before have atmospheres that look like very cool stars. This one looks like a planet."
Gas giants in our solar system formed by building up a large core over a few million years and then pulling in huge amounts of hydrogen and other gases to form an atmosphere.
This is in contrast to previously identified Jupiter-like exoplanets that appear to have formed much faster, producing very hot worlds.
Prof Macintosh added: "51 Eri b is the first one that's cold enough and close enough to the star that it could have indeed formed right where it is the 'old-fashioned way'.
"This planet really could have formed the same way Jupiter did - the whole solar system could be a lot like ours."
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