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NASA's Kepler mission has confirmed the first near-Earth-size planet in the "habitable zone' around a sun-like star. This discovery and the introduction of 11 other new small habitable zone candidate planets mark another milestone in the journey to finding another "Earth.'

The newly discovered Kepler-452b is the smallest planet to date discovered orbiting in the habitable zone -- the area around a star where liquid water could pool on the surface of an orbiting planet -- of a G2-type star, like our sun. The confirmation of Kepler-452b brings the total number of confirmed planets to 1,030. "On the 20th anniversary year of the discovery that proved other suns host
planets, the Kepler exoplanet explorer has discovered a planet and star which most closely resemble the Earth and our Sun," said John Grunsfeld, associate administrator of NASA's Science Mission Directorate at the agency's headquarters in Washington. "This exciting result brings us one step closer to finding an Earth 2.0."
Kepler-452b has a diameter 60 percent larger than Earth and is considered a super-Earth-size planet. While its mass and composition are not yet determined, previous research suggests that planets the size of Kepler-452b have a good chance of being rocky.

While Kepler-452b is larger than Earth, its 385-day orbit is only 5 percent longer. The planet is 5 percent farther from its parent star Kepler-452 than Earth is from the Sun. Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger.

"We can think of Kepler-452b as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth"s evolving environment," said Jon Jenkins, Kepler data analysis lead at NASA's Ames Research Center in Moffett Field, California, who led the team that discovered Kepler-452b. "It's awe-inspiring to consider that this planet has spent 6 billion years in the habitable zone of its star; longer than Earth. That"s substantial opportunity for life to arise, should all the necessary ingredients and conditions for life exist on this planet.'

To help confirm the finding and better determine the properties of the Kepler-452 system, the team conducted ground-based observations at the University of Texas at Austin's McDonald Observatory, the Fred Lawrence Whipple Observatory on Mt. Hopkins, Arizona, and the W. M. Keck Observatory atop Mauna Kea in Hawaii. These measurements were key for the researchers to confirm the planetary nature of Kepler-452b, to refine the size and brightness of its host star and to better pin down the size of the planet and its orbit.

The Kepler-452 system is located 1,400 light-years away in the constellation Cygnus. The research paper reporting this finding has been accepted for publication in The Astronomical Journal.

In addition to confirming Kepler-452b, the Kepler team has increased the number of new exoplanet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of planet candidates detected by the Kepler mission to 4,696. Candidates require follow-up observations and analysis to verify they are actual planets.

Twelve of the new planet candidates have diameters between one to two times that of Earth, and orbit in their star's habitable zone. Of these, nine orbit stars that are similar to our sun in size and temperature.

"We've been able to fully automate our process of identifying planet candidates, which means we can finally assess every transit signal in the entire Kepler dataset quickly and uniformly,' said Jeff Coughlin, Kepler scientist at the SETI Institute in Mountain View, California, who led the analysis of a new candidate catalog. "This gives astronomers a statistically sound population of planet candidates to accurately determine the number of small, possibly rocky planets like Earth in our Milky Way galaxy.'

These findings, presented in the seventh Kepler Candidate Catalog, will be submitted for publication in the Astrophysical Journal. These findings are derived from data publically available on the NASA Exoplanet Archive.

Scientists now are producing the last catalog based on the original Kepler mission's four-year data set. The final analysis will be conducted using sophisticated software that is increasingly sensitive to the tiny telltale signatures of Earth-size planets.

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

For more information about the Kepler mission, visit:

Michele Johnson
Ames Research Center, Moffett Field, Calif.

Felicia Chou
Headquarters, Washington

Images: NASA

NASA's Airborne Science Mission Returns to the Skies for Final Flights
March 5, 2015

NASA's Airborne Tropical Tropopause Experiment (ATTREX) returned to the skies for its fifth and final year of science flights on March 4. The remotely piloted Global Hawk research aircraft took off from its base at NASA's Armstrong Flight Research Center, Edwards, California, to track the transport of water vapor into the upper atmosphere and help researchers understand how greenhouse gases affect Earth's climate.

This year, NASA ATTREX is collaborating with United Kingdom (UK) researchers to execute their Coordinated Airborne Studies in the Tropics (CAST) project, funded by their country's Natural Environment Research Council (NERC). The mission continues to focus on the transport and exchange of greenhouse gases, in particular water vapor, in the tropical tropopause region, the transition layer between the troposphere, the lowest part of the atmosphere, and the stratosphere, the layer above it. The suite of instruments onboard includes a subset of the ATTREX payload previously flown, with a focus on cloud and water vapor measurements. In addition, two new CAST instruments will be included: the Aerosol Ice Interface Transition Spectrometer (AIITS) and the GreenHouse gas Observations in the Stratosphere and Troposphere (GHOST).

"The combination of ATTREX and CAST instruments will provide new information about the formation of tropical tropopause layer cirrus and the shapes of the ice crystals that comprise them," said Eric Jensen, the ATTREX principal investigator at NASA's Ames Research Center at Moffett Field, Calif. "The cirrus ice crystal sizes and shapes determine how fast they fall and remove water vapor from air rising into the stratosphere. The measurements made in this flight series will add to the extensive ATTREX dataset that is being used to improve our understanding of tropical tropopause layer transport and cloud processes. The science community is using this dataset to evaluate and improve global models used to predict future climate change."

Studies show that even slight changes in the amount of water vapor in the stratosphere can warm the surface temperature by absorbing thermal radiation rising from the surface.

Scientists consider the tropical tropopause to be the gateway for transport of water vapor, ozone and other gases into the stratosphere. For this mission, the Global Hawk will fly in the tropical tropopause layer (from altitudes of 45,000 to 60,000 feet) near the equator over the Pacific Ocean, providing measurements in this critical atmospheric layer.

AIITS was jointly developed by UK's Universities of Hertfordshire and Manchester. It will measure the scattering properties of aerosols and cirrus clouds, providing information about particle shapes and composition. Scientists expect these measurements, combined with those from the ATTREX Hawkeye, a cloud particle probe managed by Stratton Park Engineering (SPEC), Inc., Boulder, Colorado, and water vapor instruments, will provide valuable new information about the formation and impact of extensive, thin cirrus clouds in the tropical tropopause layer.

GHOST was jointly developed by the UK Astronomy Technology Centre in Edinburgh and the Universities of Edinburgh and Leicester. It will measure columns of greenhouse gases, such as carbon dioxide, methane, carbon monoxide and water, below the aircraft's path. It is a novel, compact Short-Wave InfraRed (SWIR) spectrometer built on similar principles to the instrument aboard the NASA Orbiting Carbon Observatory (OCO)-2 satellite launched in 2014, and will provide high spatial-resolution information about these gases as well as validation for the satellite instrument.

ATTREX will conduct three long-duration science flights totaling 66 hours. This year's flights bring the total hours flown in support of ATTREX to about 390 hours since 2011.

Jensen and Project Manager Dave Jordan of Ames have led the ATTREX mission. Investigators include four NASA facilities: Ames, Langley Research Center in Hampton, Virginia, Goddard Space Flight Center in Greenbelt, Maryland, and the Jet Propulsion Laboratory in Pasadena, California. The team also includes investigators from the National Oceanic and Atmospheric Administration, Boulder, Colorado, the National Center for Atmospheric Research, Boulder, University of Cambridge, United Kingdom, the University of California at Los Angeles, the University of Miami, Florida, the University of Heidelberg, Germany, and private industry. The project is managed by the NASA Ames Earth Science Project Office.

ATTREX is one of the first research missions of NASA's new Earth Venture project. These targeted science investigations complement NASA's research satellite missions. The Earth Venture missions are part of NASA's Earth System Science Pathfinder Program managed by Langley.

TechEdSat-4 was developed, integrated and tested at Ames by student interns with the support of co-investigators Periklis Papadopoulos, from SJSU, and DavidAtkinson, from UI. TechEdSat-4 is funded by Ames. The total cost of the satellite was less than $50,000 because the team primarily used commercial off-the-shelf hardware that was rigorously tested and simplified the design and mission objectives.

For more information about NASA's Earth science activities in 2015, visit: For more information about NASA Ames Earth Science Project Office, visit:

Jessica Culler
NASA's Ames Research Center, Moffett Field, Calif.

Image Credit: NASA Ames

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