The Kepler Spacecraft, NASA’s planet hunter, discovered three new “earth-like” planets or “Goldilocks” zones around Sun-like stars. Three of the newly-validated planets are located in their distant suns’ habitable zone, the range of distances from the host star where liquid water might exist on the surface of an orbiting planet.
Out of the three planets, two are likely made of rock, like Earth. John Grunsfeld, Associate Administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington, said, “Each result from the planet-hunting Kepler mission’s treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe.”
He added, the Kepler team and its science community continue to produce impressive results with the data from this venerable explorer, Kepler. The NASA statement says that to determine whether a planet is made of rock, water or gas, scientists must know its size and mass. When its mass can’t be directly determined, scientists can infer what the planet is made of based on its size.
Meanwhile, two of the newly validated planets, Kepler-438b and Kepler-442b, are less than 1.5 times the diameter of Earth. While Kepler-438b, 475 light-years away, is 12 percent bigger than Earth and orbits its star once every 35.2 days, Kepler-442b, 1,100 light-years away, is 33 percent bigger than Earth and orbits its star once every 112 days.
Both Kepler-438b and Kepler-442b orbit stars smaller and cooler than our Sun, making the habitable zone closer to their parent star in the direction of the constellation Lyra.
“Each result from the planet-hunting Kepler mission’s treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe,” Grunsfeld noted.
As per the NASA statement, the Kepler team has also added another 554 candidates to the roll of potential planets, six of which are near-Earth-size and orbit in the habitable zone of stars similar to our Sun.
“With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth,” said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA’s Ames Research Center at Moffett Field, California. He said, “The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”
Kepler collected data for four years, long enough that we can now tease out the Earth-size candidates in one Earth-year orbits”, said Fergal Mullally, SETI Institute Kepler scientist at Ames who led the analysis of a new candidate catalog. “We’re closer than we’ve ever been to finding Earth twins around other sun-like stars. These are the planets we’re looking for”.
However, the Kepler Space Telescope continuously monitored more than 150,000 stars beyond our solar system, and, to date, has offered scientists an assortment of more than 4,000 candidate planets for further study, the 1,000th of which was recently verified.
The research paper reporting this finding has been accepted for publication in The Astrophysical Journal.