spacetoday.net: Astronomers set new mark for smallest directly-imaged exoplanet

Posted: Sun, Aug 11, 2013, 10:07 AM ET (1407 GMT)
GJ 504b exoplanet illustration (NASA)

Astronomers announced this week the discovery of the smallest extrasolar planet to date directly observed by astronomers, a world four times the mass of Jupiter. Researchers detected the planet, GJ 504b, in near-infrared observations by the Subaru Telescope in Hawaii. The planet is thought to be relatively young, as its star is only about 160 million years old; the planet, astronomers said, would likely appear to be dull magenta in color as it glows from the heat of its formation. The planet orbits at a projected distance of 43.5 AU from its star. That distance raises questions about planet formation processes, which do not predict that planets that large would form so far from their parent star.