Keck, Gemini Assist in Discovery of Earth-Like Planet

Two Big Island observatories have helped confirm the first discovery of a planet similar in size to Earth where water could exist in liquid form.

That’s because the planet designated Kepler-186f orbits at a distance from its sun where the temperatures are not too cold and not too hot for life as we know it – an area dubbed the “Goldilocks Zone.”

The Kepler Space Telescope studied more than 150,000 stars for signs of planets over a four-year period before losing a critical component in the fall of 2013. But astronomers are still sifting through the data it collected, which includes thousands of worlds potentially like our own.

Analysis by the Keck and Gemini observatories helped confirm the presence of Kepler-186f in the habitable zone of Kepler-186, a red dwarf star located about 500 light years or 2.9 quadrillion miles from Earth.

The star is about half the size and weaker than our sun, but Kepler-186f’s orbit is smaller than Earth’s, with the planet’s year 130 Earth-days long. The result is that it receives about one-third as much heat energy as Earth, making Kepler-186f  near the outer edge of that star’s habitable zone.

Ground-based observatories have helped in the analysis of Kepler data before, including the discovery of a previous Earth-sized planet named Kepler 78b. However, that planet has an orbit of only a million miles from its sun, making it much too hot to host life.