Space

January 10, 2013

NASA’s Hubble reveals rogue planetary orbit for Fomalhaut b

nasa-hubble
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 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,” said Paul Kalas of the University of California at Berkeley and the SETI Institute in Mountain View, Calif.
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. The team presented its finding Tuesday at the 221st meeting of the American Astronomical Society in Long Beach, Calif.

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,” said co-investigator Mark Clampin of NASA’s Goddard Space Flight Center in Greenbelt, Md. “This could be the planet that gets thrown out.”

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.

Kalas hypothesized that Fomalhaut b’s extreme orbit is a major clue in explaining why the planet is unusually bright in visible light, but very dim in infrared light. It is possible the planet’s optical brightness originates from a ring or shroud of dust around the planet, which reflects starlight. The dust would be rapidly produced by satellites orbiting the planet, which would suffer extreme erosion by impacts and gravitational stirring when Fomalhaut b enters into the planetary system after a millennium of deep freeze beyond the main belt. An analogy can be found by looking at Saturn, which has a tenuous, but very large dust ring produced when meteoroids hit the outer moon Phoebe.

The team has also considered a different scenario where a hypothetical second dwarf planet suffered a catastrophic collision with Fomalhaut b. The collision scenario would explain why the star Fomalhaut has a narrow outer belt linked to an extreme planet. But in this case the belt is young, less than 10,000 years old, and it is difficult to produce energetic collisions far from the star in such young systems.

Fomalhaut is a special system because it looks like scientists may have a snapshot of what our solar system was doing 4 billion years ago. The planetary architecture is being redrawn, the comet belts are evolving, and planets may be gaining and losing their moons. Astronomers will continue monitoring Fomalhaut b for decades to come because they may have a chance to observe a planet entering an icy debris belt that is like the Kuiper Belt at the fringe of our own solar system.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines April 14, 2014

Business: U.S. Navy looks to leverage submarine work to keep costs down - The U.S. Navy hopes to save money and time by leveraging industry investments as it replaces its Ohio-class nuclear-armed submarines with the Virginia-class attack submarines now built by General Dynamics Corp and Huntington Ingalls Industries Inc.  Study raises red flags on California aerospace...
 
 

News Briefs April 14, 2014

U.S. Navy destroyer Zumwalt christened in Maine The U.S. Navy has christened the first ship of its newest class of destroyers, a 610-foot (186-meter)-long warship with advanced technologies and a stealthy design that will reduce its visibility on enemy radars. The warship bears the name of the late Adm. Elmo ìBudî Zumwalt, who became the...
 
 
Navy photograph by Seamn Edward Guttierrez III

Russian aircraft flies near U.S. Navy ship in Black Sea

Navy photograph by Seamn Edward Guttierrez III Sailors man the rails as the Arleigh Burke-class guided-missile destroyer USS Donald Cook arrives at Naval Station Rota, Spain, Feb. 11, 2014. Donald Cook is the first of four Arle...
 

 

45th Space Wing launches NRO Satellite on board Atlas V

The 45th Space Wing successfully launched a United Launch Alliance Atlas V rocket from Space Launch Complex 41, Vandenberg Air Force Base, Calif., at 1:45 p.m. April 10 carrying a classified national security payload. The payload was designed and built by the National Reconnaissance Office. “I am proud of the persistence and focus of the...
 
 

U.S. Air Force selects Cubic for Moroccan P5 air combat training system

Cubic Defense Systems, a subsidiary of Cubic Corporation announced April 11 it has been awarded a contract valued at more than $5 million from the U.S. Air Force to supply its P5 Combat Training System to the Moroccan Air Force. Morocco will join the United States Air Force, Navy, and Marine Corps, along with a...
 
 
Lockheed Martin photograph

NASA’s Orion Spacecraft powers through first integrated system testing

Lockheed Martin photograph Engineers in the Operations and Checkout Building at NASA’s Kennedy Space Center in Florida, perform avionics testing on the Orion spacecraft being prepared for its first trip to space later this ye...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>