"Zombie" Planet Fomalhaut B Has Weird Orbit That Befuddles Astronomers
New observations of the planet Fomalhaut b by the Hubble Space Telescope has left astronomers scratching their heads. The so-called "zombie" planet's unbalanced orbit in a dusty star system has left astronomers struggling to explain the exoplanets behavior.
The strange orbit features wild extremes between its closest and farthest points from the parent star, and also appears to cross through a vast minefield of dusty debris.
Study leader Paul Kalas, an astronomer with the University of California at Berkley and the SETI Institute in Mountain View, Calif., said in a statement on Tuesday:
"We are shocked. This is not what we expected."
Fomalhaut b is a massive alien planet that is nearly three times the mass of Jupiter, and was the first alien planet ever directly imaged in visible light. It orbits the dust-shrouded star Fomalhaut, and is located about 25 light-years away from Earth in the constellation Piscis Austrinus.
Scientists dubbed the world a "zombie planet" in October 2012 because it appeared to have risen from the academic grave. After it was first discovered in 2008, subsequent studies had shown that the planet was nothing more than a huge dust cloud. But in 2012, astronomers resurrected Fomalhaut b's planet status when new observations proved that there was a planetary object embedded in a free-floating dust cloud.
The planet's latest observations reveal that the dusty debris disk that surrounds Fomalhaut is much wider than once thought. The debris belt spans a large region of space between 14 billion and 20 billion miles around the star. Even stranger, the planet Fomalhaut b looks to approach with 4.6 billion miles of its star at the closest point in its orbit, and then swings far out to a point 27 billion miles away at the farthest point. Astronomers call the extremes of such a planet's path a "highly eccentric orbit."
Fomalhaut b's path sends the planet crashing through the surrounding debris disk during its 2,000 year long orbit around its parent star.
The research was unveiled on Tuesday at the 221st meeting of the American Astronomical Society in Long Beach, Calif.
There are a few theories being floated to explain Fomalhaut b's odd orbit. One is the possibility that the exoplanet had an encounter with another planet that has yet to be discovered. The close encounter could have gravitationally ejected Fomalhaut b into its current orbit.
Study co-investigator Mark Clampin of NASA's Goddard Space Flight Center in Greenbelt, Md. said in a statement:
"Hot Jupiters get tossed through scattering events, where one planet goes in and one gets thrown out. This could be the planet that gets thrown out."