Space Telescope Science
Newly released Hubble Space Telescope images of a vast debris disk encircling the nearby star Fomalhaut, and of a mysterious planet circling it, may provide forensic evidence of a titanic planetary disruption in the system. Astronomers are surprised to find that the debris belt is wider than previously known, spanning a gulf of space from 14 billion miles to nearly 20 billion miles from the star. Even more surprisingly, the latest Hubble images have allowed a team of astronomers to calculate that the planet follows an unusual elliptical orbit that carries it on a potentially destructive path through the vast dust ring.
The planet, called Fomalhaut b, swings as close to its star as 4.6 billion miles, and the outermost point of its orbit is 27 billion miles away from the star. The orbit was re-calculated from the newest Hubble observation made in 2012. The Fomalhaut team led by Paul Kalas (University of California, Berkeley) considers this circumstantial evidence that there may be other planet-like bodies in the system that gravitationally disrupted Fomalhaut b to place it in such a highly eccentric orbit. His team is presenting their finding today at the 221st meeting of the American Astronomical Society in Long Beach, Calif.