Star's oversized debris ring challenges theories of planet formation
ANCHORAGE, Alaska — About 80 light-years away, an enormous, dusty ring swirls around a sunlike star, with a defined inner edge that is probably sculpted by a planet orbiting at 140 times Earth’s distance from the sun.
A planet located so far from a sunlike star presents an astronomical conundrum.
“How do you get a planet out that far? We don’t know how to form something out there,” astronomer Karl Stapelfeldt of NASA’s Goddard Space Flight Center in Greenbelt, Md., said on June 14 at the 220th Meeting of the American Astronomical Society.
Stapelfeldt and a team led by John Krist of the Jet Propulsion Laboratory in Pasadena, Calif., used the Hubble Space Telescope to study 10 stars suspected of hosting large debris disks. Hubble saw a ring around only one, HD 202628, which resides in the southern constellation Microscopium.
Everything about the dusty circle — the biggest ever observed around a solar cousin &mdash