Using NASA’s Kepler Space Telescope, astronomers have discovered a super-Earth exoplanet in the ‘habitable zone’ of a G2-type star called Kepler-452.

The Kepler-452 system is located in the constellation Cygnus, approximately 1,400 light-years away.

It’s estimated that the star itself is approximately 6 billion years old – 1.5 billion years older than our Sun. The star has the same temperature (5,757 K), and is 20% brighter and has a diameter 10% larger.

The newfound planet, named Kepler-452b, is around 60% larger in diameter than Earth and is 5% farther from its parent star than Earth is from the Sun.

The planet has an orbital period around 385 days (only 5% longer than an Earth year).

“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 Dr Jon Jenkins of NASA’s Ames Research Center, team member and lead author of the discovery paper published in the Astronomical Journal.

“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.”

The discovery and confirmation of Kepler-452b brings the total number of confirmed exoplanets to 1,030.

In addition to this discovery, Dr Jenkins and co-authors have increased the number of planet candidates by 521 from their analysis of observations conducted from May 2009 to May 2013, raising the number of exoplanet candidates detected by Kepler to 4,696.

Twelve of the new candidate exoplanets have diameters 1-2 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 co-author Dr Jeff Coughlin of the SETI Institute in Mountain View, California.

“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.”

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Jon M. Jenkins et al. 2015. Discovery and Validation of Kepler-452b: A 1.6 RO Super Earth Exoplanet in the Habitable Zone of a G2 Star. Astronomical Journal 150, 56; doi: 10.1088/0004-6256/150/2/56