Volunteers from the Planethunters website have identified 15 new habitable planet candidates among data collected by NASA's Kepler spacecraft.

One of the 15, a Jupiter-sized planet orbiting the solar-type star KIC 12735740, has been officially confirmed as a planet (with 99.9 percent certainty). Named PH2 b, it is the second confirmed planet to be found by Planethunters.org, part of the Oxford University-led Zooniverse citizen science project that turns raw data over to keen amateur researchers. The remaining 14 planet candidates are at least 90 percent likely to be planets.

[partner id="wireduk"]Launched in March 2007, Nasa's Kepler spacecraft has been searching for undiscovered exoplanets in the habitable zone of their parent stars using a wavelet-based algorithm called transit planet search, which detects the moment a planet passes in front of its star. While the algorithm will spot the vast majority of planet candidates, a small number will go unnoticed. Since 2010, Planethunters has been searching through the Kepler data NASA released into the public domain, allowing its 200,000-strong army of volunteers to seek out the telltale dip in the brightness of parent stars as planets pass in front of them.

Added to the 19 similar planets already discovered in habitable zones, where the temperature is neither too hot nor too cold for liquid water, the new finds present exciting possibilities for the discovery of regions that could potentially support life – not only on the planets themselves, but also on their moons.

"There's an obsession with finding Earth-like planets but what we are discovering, with planets such as PH2 b, is far stranger," explained Zooniverse lead Chris Lintott of Oxford University in a press release Jan. 7. "Jupiter has several large water-rich moons – imagine dragging that system into the comfortably warm region where the Earth is. If such a planet had Earth size moons, we'd see not Europa and Callisto, but worlds with rivers, lakes and all sorts of habitats – a surprising scenario that might just be common.

"These are planet candidates that slipped through the net, being missed by professional astronomers and rescued by volunteers in front of their web browsers. It's remarkable to think that absolutely anyone can discover a planet."

Planethunters lead scientist Debra Fischer of Yale University said in the press release: "We are seeing the emergence of a new era in the Planet Hunters project where our volunteers seem to be at least as efficient as the computer algorithms at finding planets orbiting at habitable zone distances from the host stars. Now, the hunt is not just targeting any old exoplanet – volunteers are homing in on habitable worlds."

The report of the research submitted to the Astrophysical Journal acknowledges more than 40 volunteers for their contributions to the work, including 71-year-old Roy Jackson, a retired police officer living in Birtley, Gateshead. "It is difficult to put into words the pleasure, wonderment and perhaps even pride that I have in some small way been able to assist in the discovery of a planet," he said in the press release. "But I would like to say that the discovery makes the time spent on the search well worth the effort."

Source: Wired UK