Illustration by Dana Berry, National Geographic
Published July 6, 2012
Astronomers have detected our "grotesque" twin: A planetary system arranged much like our own solar system, a new study says.
Dubbed GJ676A, the system has two rocky planets orbiting close to its host star, and two gas giants orbiting far away. This means the system is arranged like our system—though in GJ676A, everything is much larger.
Other multiple-planet systems have been discovered, such as HD10180, which has been called the richest exoplanetary find ever because of the seven to nine planets orbiting its host star. (Also see "Our Solar System May Have Millions of 'Twins.'")
But HD10180's planets are all gas giants in relatively close orbits, while GJ676A has both rocky and gas planets—and its "Neptune-like" planet takes 4,000 days to make one orbit, said study leader Guillem Anglada Escudé, a postdoctoral researcher at the University of Gottingen in Germany.
The long orbits of GJ676A's gas giants and the short orbits of its close-in, extremely hot super Earths are what led the astronomers to dub GJ676A our solar system's twin.
"Hidden" Planets Detected Via New Technique
Anglada Escudé and team used a new data-analysis technique to detect smaller planets around the star, which had already been known to host one gas giant.
"This means that it's likely that other systems have hidden companions," he said. "We just need to apply the new techniques to find them."
The finding also may refine planetary-formation models, he added. According to one popular explanation for super Earths so close to a host star, the planets form farther out and migrate inward.
"But your planet that moves picks up all the mass with it," Anglada Escudé said.
"That didn't happen here, because you still had mass to form the gas giants. It's possible that the gas giants formed first in long-period orbits—they didn't migrate—and then a few million years later, you start forming super-Earths with the leftovers."
The grotesque-twin research appears in ArXiv.
From herding sheep in Mongolia to supercell thunderstorms in Oklahoma, see a gallery of the best user submitted photos this year.
Hoverboards, flying cars, automatic fill-ups, and fuel from garbage—the energy ideas in 'Back to the Future' are close at hand.
Fracking for shale oil has boosted U.S. oil production to near-record levels. But the industry faces two challenges: low prices and low reserves.
The Future of Food
How do we feed nine billion people by 2050, and how do we do so sustainably?
We've made our magazine's best stories about the future of food available in a free iPad app.