Washington DC : NASA’s Kepler mission has found Earth’s older bigger cousin 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 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. Kepler-452b is 60 percent larger in diameter 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. Jon Jenkins, who led the team that discovered Kepler-452b, said that Kepler-452b could be thought of as an older, bigger cousin to Earth, providing an opportunity to understand and reflect upon Earth’s evolving environment.
It’s awe-inspiring to consider that this planet had 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, he added. The research will soon be published in The Astronomical Journal.