Washington: Newly released NASA Hubble Space Telescope images of a vast debris disk encircling the nearby star Fomalhaut and 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 section of space from 14 to nearly 20 billion miles from the star.
Even more surprisingly, the latest Hubble images have allowed a team of astronomers to calculate 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 recalculated from the newest Hubble observation made last year.
"We are shocked. This is not what we expected," Paul Kalas of the University of California at Berkeley and the SETI Institute in Mountain View, California said.
The Fomalhaut team led by Kalas considers this circumstantial evidence there may be other planet-like bodies in the system that gravitationally disturbed Fomalhaut b to place it in such a highly eccentric orbit.
Among several scenarios to explain Fomalhaut b`s 2,000-year-long orbit is the hypothesis that an as yet undiscovered planet gravitationally ejected Fomalhaut b from a position closer to the star, and sent it flying in an orbit that extends beyond the dust belt.
"Hot Jupiters get tossed through scattering events, where one planet goes in and one gets thrown out," co-investigator Mark Clampin of NASA`s Goddard Space Flight Center in Greenbelt, Md said.
"This could be the planet that gets thrown out," he said.
Hubble also found the dust and ice belt encircling the star Fomalhaut has an apparent gap slicing across the belt.
This might have been carved by another undetected planet. Hubble`s exquisite view of the dust belt shows irregularities that strongly motivate a search for other planets in the system.
If its orbit lies in the same plane with the dust belt, then Fomalhaut b will intersect the belt around 2032 on the outbound leg of its orbit.
During the crossing, icy and rocky debris in the belt could crash into the planet`s atmosphere and create the type of cosmic fireworks seen when Comet Shoemaker-Levy 9 crashed into Jupiter.
Most of the fireworks from collisions will be seen in infrared light.
However, if Fomalhaut b is not co-planar with the belt, the only thing to be seen will be a gradual dimming of Fomalhaut b as it travels farther from the star.