NASA’s Kepler mission discovers Earth’s larger, older cousin
Scientists with NASA’s Kepler mission announced on Thursday, July 23, the confirmation of the first near-Earth-size planet in the “habitable zone” around a Sun-like star. The newly discovered planet, Kepler-452b, is the smallest planet found to date that orbits a Sun-like star in the habitable zone, the area around a star where liquid water could pool on the planet’s surface. The confirmation of Kepler-452b brings the 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 is about 60 percent larger than Earth in diameter, which puts it into the category of a super-Earth-size planet.
While previous research indicated that planets of Kepler-452b’s general size have a good chance of being rocky, its mass and composition have yet to be determined.
As is the case with all exoplanets, scientists from different points across the globe will study this newly-discovered world and work to validate or disprove these initial findings.
Kepler-452b’s 385-day long orbit is approximately 5 percent longer than Earth’s. The planet is also 5 percent farther from Kepler-452, the star that it orbits, than the Earth is from the Sun.
Kepler-452 is 6 billion years old, 1.5 billion years old than the Sun and has the same temperature. The star has a 10 percent larger diameter than the Sun and is 20 percent brighter.
“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.”
In order to confirm the finding and learn more about 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 in Arizona, and the W. M. Keck Observatory atop Mauna Kea in Hawaii.
These observations were important in terms of confirming that Kepler-452b was actually a planet. They helped researchers to establish the planet’s size as well as its orbit, and to refine the size and brightness of its parent star.
The Kepler-452 system is 1,400 light-years from Earth, in the constellation Cygnus. The paper documenting this discovery will be published in The Astronomical Journal.
In addition to Kepler-452b, there are 11 other habitable zone candidate planets that are between one and two times the diameter of the Earth in size. These potential planets are part of a group of 521 candidates that resulted from analysis of observations conducted from May 2009 to May 2013. Further observations and analysis will be required to confirm that the candidates are actual planets.
The Kepler spacecraft was launched on March 7, 2009, atop a United Launch Alliance Delta II rocket from Cape Canaveral Air Force Station’s Space Launch Complex 17-B (SLC-17B) located in Florida. On April 7, 2009, the cover of the telescope was jettisoned into space and the first images were captured on the following day.
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.