Space

July 18, 2012

NASA’s Spitzer find evidence for an explanet smaller than Earth

Astronomers using NASA’s Spitzer Space Telescope have detected what they believe is a planet two-thirds the size of Earth.

The exoplanet candidate, called UCF-1.01, is located a mere 33 light-years away, making it possibly the nearest world to our solar system that is smaller than our home planet.

Exoplanets circle stars beyond our sun. Only a handful smaller than Earth have been found so far. Spitzer has performed transit studies on known exoplanets, but UCF-1.01 is the first ever identified with the telescope, pointing to a possible role for Spitzer in helping discover potentially habitable, terrestrial-sized worlds.

“We have found strong evidence for a very small, very hot and very near planet with the help of the Spitzer Space Telescope,” said Kevin Stevenson from the University of Central Florida in Orlando. Stevenson is lead author of the paper, which has been accepted for publication in The Astrophysical Journal. “Identifying nearby small planets such as UCF-1.01 may one day lead to their characterization using future instruments.”

The hot new planet candidate was found unexpectedly in Spitzer observations. Stevenson and his colleagues were studying the Neptune-sized exoplanet GJ 436b, already known to exist around the red-dwarf star GJ 436. In the Spitzer data, the astronomers noticed slight dips in the amount of infrared light streaming from the star, separate from the dips caused by GJ 436b. A review of Spitzer archival data showed the dips were periodic, suggesting a second planet might be blocking out a small fraction of the star’s light.

This technique, used by a number of observatories including NASA’s Kepler space telescope, relies on transits to detect exoplanets. The duration of a transit and the small decrease in the amount of light registered reveals basic properties of an exoplanet, such as its size and distance from its star. In UCF-1.01’s case, its diameter would be approximately 5,200 miles (8,400 kilometers), or two-thirds that of Earth. UCF-1.01 would revolve quite tightly around GJ 436, at about seven times the distance of the Earth from the moon, with its “year” lasting only 1.4 Earth days. Given this proximity to its star, far closer than the planet Mercury is to our sun, the exoplanet’s surface temperature would be more than 1,000 degrees Fahrenheit (almost 600 degrees Celsius).

If the roasted, diminutive planet candidate ever had an atmosphere, it almost surely has evaporated. UCF-1.01 might therefore resemble a cratered, mostly geologically dead world like Mercury. Paper co-author Joseph Harrington, also of the University of Central Florida and principal investigator of the research, suggested another possibility; that the extreme heat of orbiting so close to GJ 436 has melted the exoplanet’s surface.

“The planet could even be covered in magma,” Harrington said.

In addition to UCF-1.01, Stevenson and his colleagues noticed hints of a third planet, dubbed UCF-1.02, orbiting GJ 436. Spitzer has observed evidence of the two new planets several times each. However, even the most sensitive instruments are unable to measure exoplanet masses as small as UCF-1.01 and UCF-1.02, which are perhaps only one-third the mass of the Earth. Because knowing the mass is required for confirming a discovery, the paper authors are cautiously calling both bodies exoplanet candidates for now.

Of the approximately 1,800 stars identified by Kepler as candidates for having planetary systems, just three are verified to contain sub-Earth-sized exoplanets. Of these, only one exoplanet is thought to be smaller than the Spitzer candidates, with a radius similar to Mars, or 57 percent that of Earth.

“I hope future observations will confirm these exciting results, which show Spitzer may be able to discover exoplanets as small as Mars,” said Michael Werner, Spitzer Project Scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “Even after almost nine years in space, Spitzer’s observations continue to take us in new and important scientific directions.”

JPL manages Spitzer for NASA’s Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Caltech manages JPL for NASA.




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


 
 

 

Headlines May 27, 2015

News: U.S. Air Force certifies SpaceX for military launches - SpaceX has been certified for military space launch, the U.S. Air Force announced May 26. The long-awaited announcement is a game changer, with SpaceX becoming only the second provider cleared by the service to launch national security payloads into orbit.   Business: Northrop Grumman CEO issues...
 
 

New’s Briefs May 27, 2015

U.S. military begins search flights for stranded Rohingya The United States has begun military surveillance flights to help locate stranded Rohingya and Bangladeshi boat people in Southeast Asian seas. State Department spokesman Jeff Rathke said May 26 that U.S. Navy P8 aircraft flew over the weekend with Malaysian support. Rathke said the U.S. has offered...
 
 
nasa-commercial-crew

Commercial Crew milestones met; partners on track for 2017 missions

NASA has taken another step toward returning America’s ability to launch crew missions to the International Space Station from the United States in 2017. The Commercial Crew Program ordered its first crew rotation mission fro...
 

 
af-spacex

Air Force certifies SpaceX for national security space missions

Lt. Gen. Samuel Greaves, commander of the Air Force Space and Missile Systems Center and Air Force program executive officer for space, has announced the certification of Space Exploration Technologies Corporation’s Falco...
 
 

Northrop Grumman passes key design review for B-2 weapons management upgrade

Northrop Grumman has successfully demonstrated to the U.S. Air Force that its plans to upgrade key weapons management software for the B-2 stealth bomber are on track and ready to proceed to the next level of development. The company successfully completed the critical design review of the service’s Flexible Strike Phase 1 program on Feb...
 
 
boeing-space

Boeing awarded first-ever commercial human spaceflight mission

NASA issued a task order as part of Boeing’s $4.2 billion Commercial Crew Transportation Capability contract recently to include the company’s first-ever service flight to the International Space Station. The award ...
 




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>