LOS ANGELES — Using a brand-new technique, scientists using NASA’s Kepler Space Telescope have found 715 confirmed planets huddling around 305 stars, nearly triple Kepler’s previous total of 246 confirmed planets in the Milky Way galaxy. Nearly 95 percent of them are smaller than Neptune, and four of them are in their star’s habitable zone, the region where liquid water — a necessary ingredient for life as we know it — could exist.
Even though the planet-hunting telescope’s crucial pointing ability was crippled last year, data mined from the spacecraft are still turning up a trove of strange and wonderful worlds, researchers said — bringing them ever closer to finding “Earth 2.0.”
“We’ve been able to open the bottleneck to access the mother lode and deliver to you more than 20 times as many planets as have ever been found and announced at once,” said Jack Lissauer, a planetary scientist at NASA Ames Research Center who co-led one of two papers on the discovery published in the Astrophysical Journal.
The research, which covers the first two years of data after Kepler’s 2009 launch, has turned up a smorgasbord of smaller planets — and all in multi-planet systems. The scientists increased the number of confirmed Earth-sized planets by 400 percent, super-Earths by 500 percent and Neptune-sized planets by 200 percent. The number of Jupiter-sized worlds, on the other hand, rose by a mere 2 percent.
This highlights the transition away from the massive gas giants that characterized Kepler’s first finds and more toward planets that are in the right size range to potentially host life as we know it.
“Certainly it will have ramifications for any mission that finds planets,” Kepler project scientist Steve Howell said of the findings.
Kepler gets better at finding smaller planets with longer periods over time, because it has more time to search for the tiny shadows they cast as they pass in front of their home stars. This mission collected about four years of data before two of its reaction wheels failed, crippling the spacecraft. (Plans to repurpose the spacecraft, called K2, are currently in the works.)