Space

June 14, 2013

Hubble uncovers evidence of farthest planet forming from its star

nasa-hubble
using NASA’s Hubble Space Telescope have found compelling evidence of a planet forming 7.5 billion miles away from its star, a finding that may challenge current theories about planet formation.

Of the almost 900 planets outside our solar system that have been confirmed to date, this is the first to be found at such a great distance from its star. The suspected planet is orbiting the diminutive red dwarf TW Hydrae, a popular astronomy target located 176 light-years away from Earth in the constellation Hydra the Sea Serpent.

Hubble’s keen vision detected a mysterious gap in a vast protoplanetary disk of gas and dust swirling around TW Hydrae. The gap is 1.9 billion miles wide and the disk is 41 billion miles wide. The gap’s presence likely was caused by a growing, unseen planet that is gravitationally sweeping up material and carving out a lane in the disk, like a snow plow.

The planet is estimated to be relatively small, at 6 to 28 times more massive than Earth. Its wide orbit means it is moving slowly around its host star. If the suspected planet were orbiting in our solar system, it would be roughly twice Pluto’s distance from the sun.

Planets are thought to form over tens of millions of years. The buildup is slow, but persistent as a budding planet picks up dust, rocks, and gas from the protoplanetary disk. A planet 7.5 billion miles from its star should take more than 200 times longer to form than Jupiter did at its distance from the sun because of its much slower orbital speed and the deficiency of material in the disk. Jupiter is 500 million miles from the sun and it formed in about 10 million years.

TW Hydrae is only 8 million years old, making it an unlikely star to host a planet, according to this theory. There has not been enough time for a planet to grow through the slow accumulation of smaller debris. Complicating the story further is that TW Hydrae is only 55 percent as massive as our sun.
“It’s so intriguing to see a system like this,” said John Debes of the Space Telescope Science Institute in Baltimore, Md. Debes leads a research team that identified the gap. “This is the lowest-mass star for which we’ve observed a gap so far out.”

An alternative planet-formation theory suggests that a piece of the disk becomes gravitationally unstable and collapses on itself. In this scenario, a planet could form more quickly, in just a few thousand years.
“If we can actually confirm that there’s a planet there, we can connect its characteristics to measurements of the gap properties,” Debes said. “That might add to planet formation theories as to how you can actually form a planet very far out.”

The TW Hydrae disk also lacks large dust grains in its outer regions. Observations from the Atacama Large Millimeter Array in Chile show dust grains roughly the size of a grain of sand are not present beyond about 5.5 billion miles from the star, just short of the gap.

“Typically, you need pebbles before you can have a planet. So, if there is a planet and there is no dust larger than a grain of sand farther out, that would be a huge challenge to traditional planet formation models,” Debes said.

The team used Hubble’s Near Infrared Camera and Multi-Object Spectrometer (NICMOS) to observe the star in near-infrared light. The researchers then compared the NICMOS images with archival Hubble data and optical and spectroscopic observations from Hubble’s Space Telescope Imaging Spectrograph (STIS). Debes said researchers see the gap at all wavelengths, which indicates it is a structural feature and not an illusion caused by the instruments or scattered light.

The team’s paper will appear online June 14 in The Astrophysical Journal.




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>