Kepler Telescope Discovers 715 New Planets

NASA’s Kepler Space Telescope may be down, but it’s not out, and its data collection is the gift that keeps giving.

Scientists on Wednesday announced the discovery of 715 new exoplanets. As the largest windfall of validated planets the space agency has ever revealed at one time, it doubles the number of planets known to humanity outside our solar system.

All of these planets exist within multi-planet systems similar to our own, and 95 percent are smaller than Neptune. Four are even within the habitable zone, which means they could theoretically support life-giving liquid water on their surfaces.

“We’ve been able to open the bottleneck to access the mother lode and deliver to you more than 20 times the planets than had ever been announced previously,” said Jack Lissauer, planetary scientist at NASA Ames Research Center.

Kepler’s latest delivery opens up fresh territory, allowing astronomers to study both individual planets and their configurations within planetary systems.

Since Kepler launched in March 2009, it has identified more than 3,600 possible exoplanets, but most have yet to be confirmed — a process that requires further observation of each candidate world. To this point, confirming planets has been a laborious, slow process. However, scientists used a new statistical technique to open the bottleneck and find hundreds of new planets with relative ease.

Kepler detects planetary candidates by measuring the brief dimming of a star’s brightness as an object passes in front of it, which is called the transit method. This scientific trick is more than 90 percent accurate, but non-planetary bodies can show up as false positives — like when one star crosses in front of another in a binary system.

The new technique, called verification by multiplicity, allowed scientists to weed out instances that couldn’t possibly have been caused by eclipsing stars, eliminating the false-positive problem.

The multiplicity method relies partly on the logic of probability. Distinguishing between a planet orbiting a star and a star orbiting  a star is difficult. But when a third body appears in a transit signal, the chance it is another star is less than 1 percent. A trio of orbiting stars likely wouldn’t line up the way Kepler likes, with two stars passing directly in front of the third, blocking its light and creating the dips that Kepler sees. So when astronomers see Keplerian evidence of a third body, they can be almost certain they’ve found more planets.

Kepler observed hundreds of stars with multiple planet candidates, and careful study of this sample allowed scientists to verify this next big batch of worlds.

“We built upon a lot of past work that has been vetted and reused by the community,” said Sara Seager, professor of Physics and Planetary Science at MIT. “It has a new aspect to it based on probability.”

The multiplicity technique will help scientists efficiently pore through the remaining two years of data from Kepler, which will likely yield hundreds more verified exoplanets.

Photo credit: Kepler Mission/NASA

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Mothballed telescope gets new life as asteroid hunter

By Irene Klotz

CAPE CANAVERAL, Florida | Wed Aug 21, 2013 7:24pm EDT

CAPE CANAVERAL, Florida (Reuters) - NASA will reactivate a mothballed infrared space telescope for a three-year mission to search for potentially dangerous asteroids on a collision course with Earth, officials said on Wednesday.

The Wide-field Infrared Survey Explorer, or WISE, telescope also will hunt for targets for a future mission to send a robotic spacecraft to rendezvous with a small asteroid and relocate all or part of it into a high orbit around the moon.

Astronauts would then visit the relocated asteroid during a test flight of NASA's deep-space Orion capsule, scheduled for launch around 2021. Orion and a heavy-lift rocket called the Space Launch System are slated for an unmanned debut test flight in 2017.

NASA is spending about $3 billion a year for Orion and Space Launch System development.

Launched in December 2009, the WISE telescope spent 13 months scouting for telltale infrared signs of asteroids, stars, distant galaxies and other celestial objects, especially those too dim to radiate in visible light.

As part of its all-sky mapping mission, WISE observed more than 34,000 asteroids in the main asteroid belt between Mars and Jupiter and another 135 asteroids in orbits that come close to Earth.

Overall, scientists cataloged more than 560 million objects with WISE.

Most of the telescope's instruments were turned off when its primary mission was completed in February 2011.

NASA plans to bring WISE out of hibernation next month and operate it for another three years, at a cost of about $5 million per year, said NASA spokesman Dwayne Brown.

"After a quick checkout, we're going to hit the ground running," WISE astronomer Amy Mainzer, with NASA's Jet Propulsion Laboratory in Pasadena, California, said in a statement.

NASA already has found about 95 percent of the near-Earth asteroids that are .62 miles or larger in diameter.

The agency is about halfway through a 15-year effort to find 90 percent of all near-Earth objects that are as small as about 459 feet in diameter.

The search took on a note of urgency after a small asteroid blasted through the skies above Chelyabinsk, Russia, in February 2013 and exploded with 20- to 30 times the force of the Hiroshima atomic bomb. More than 1,500 people were injured by flying glass and debris.

Later that same day, a much larger but unrelated asteroid soared closer to Earth than the networks of communication satellites that ring the planet.

The events prompted Congressional hearings and new calls for NASA and other agencies to step up their asteroid detection initiatives.

The Obama administration proposes to double NASA's $20 million Near-Earth Objects detection programs for the 2014 fiscal year beginning October 1.

About 66 million years ago, an object 6 miles in diameter smashed into what is now the Yucatan Peninsula in Mexico, leading to the demise of the dinosaurs, as well as most plant and animal life on Earth.

(Editing by Kevin Gray)

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NASA Space Telescope Finds Fewer Asteroids Near Earth

NEOWISE observations indicate that there are at least 40 percent fewer near-Earth asteroids in total that are larger than 330 feet, or 100 meters. Our solar system's four inner planets are shown in green, and our sun is in the center. Each red dot represents one asteroid. Object sizes are not to scale. Image credit: NASA/JPL-Caltech
› Larger image | › See animation September 29, 2011

PASADENA, Calif. -- New observations by NASA's Wide-field Infrared Survey Explorer, or WISE, show there are significantly fewer near-Earth asteroids in the mid-size range than previously thought. The findings also indicate NASA has found more than 90 percent of the largest near-Earth asteroids, meeting a goal agreed to with Congress in 1998.

Astronomers now estimate there are roughly 19,500 -- not 35,000 -- mid-size near-Earth asteroids. Scientists say this improved understanding of the population may indicate the hazard to Earth could be somewhat less than previously thought. However, the majority of these mid-size asteroids remain to be discovered. More research also is needed to determine if fewer mid-size objects (between 330 and 3,300-feet wide) also mean fewer potentially hazardous asteroids, those that come closest to Earth.

The results come from the most accurate census to date of near-Earth asteroids, the space rocks that orbit within 120 million miles (195 million kilometers) of the sun into Earth's orbital vicinity. WISE observed infrared light from those in the middle to large-size category. The survey project, called NEOWISE, is the asteroid-hunting portion of the WISE mission. Study results appear in the Astrophysical Journal.

"NEOWISE allowed us to take a look at a more representative slice of the near-Earth asteroid numbers and make better estimates about the whole population," said Amy Mainzer, lead author of the new study and principal investigator for the NEOWISE project at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "It's like a population census, where you poll a small group of people to draw conclusions about the entire country."

WISE scanned the entire celestial sky twice in infrared light between January 2010 and February 2011, continuously snapping pictures of everything from distant galaxies to near-Earth asteroids and comets. NEOWISE observed more than 100 thousand asteroids in the main belt between Mars and Jupiter, in addition to at least 585 near Earth.

WISE captured a more accurate sample of the asteroid population than previous visible-light surveys because its infrared detectors could see both dark and light objects. It is difficult for visible-light telescopes to see the dim amounts of visible-light reflected by dark asteroids. Infrared-sensing telescopes detect an object's heat, which is dependent on size and not reflective properties.

Though the WISE data reveal only a small decline in the estimated numbers for the largest near-Earth asteroids, which are 3,300 feet (1 kilometer) and larger, they show 93 percent of the estimated population have been found. This fulfills the initial "Spaceguard" goal agreed to with Congress. These large asteroids are about the size of a small mountain and would have global consequences if they were to strike Earth. The new data revise their total numbers from about 1,000 down to 981, of which 911 already have been found. None of them represents a threat to Earth in the next few centuries. It is believed that all near-Earth asteroids approximately 6 miles (10 kilometers) across, as big as the one thought to have wiped out the dinosaurs, have been found.

"The risk of a really large asteroid impacting the Earth before we could find and warn of it has been substantially reduced," said Tim Spahr, the director of the Minor Planet Center at the Harvard Smithsonian Center for Astrophysics in Cambridge, Mass.

The situation is different for the mid-size asteroids, which could destroy a metropolitan area if they were to impact in the wrong place. The NEOWISE results find a larger decline in the estimated population for these bodies than what was observed for the largest asteroids. So far, the Spaceguard effort has found and is tracking more than 5,200 near-Earth asteroids 330 feet or larger, leaving more than an estimated 15,000 still to discover. In addition, scientists estimate there are more than a million unknown smaller near-Earth asteroids that could cause damage if they were to impact Earth.

"NEOWISE was just the latest asset NASA has used to find Earth's nearest neighbors," said Lindley Johnson, program executive for the Near Earth Object Observation Program at NASA Headquarters in Washington. "The results complement ground-based observer efforts over the past 12 years. These observers continue to track these objects and find even more."

WISE is managed and operated by JPL for NASA's Science Mission Directorate in Washington. The principal investigator, Edward Wright, is at the University of California, Los Angeles. The WISE science instrument was built by the Space Dynamics Laboratory in Logan, Utah, and the spacecraft was built by Ball Aerospace and Technologies Corp. in Boulder, Colo. Science operations and data processing occur at the Infrared Processing and Analysis Center at the California Institute of Technology.

For more information about the mission, visit: http://www.nasa.gov/wise .

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
Whitney.clavin@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

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