A University of Hawaii astronomer is part of a team that has discovered a "super-Earth" using a creative approach to make up for a mechanical glitch aboard the star-gazing Kepler spacecraft.

The newfound planet, HIP 116454b, has a diameter of 20,000 miles, 2 1⁄2 times the size of Earth, and weighs almost 12 times as much as Earth. This makes HIP 116454b a super-Earth, a class of planets that doesn’t exist in our solar system.

The average density suggests that this planet is either a water world composed of about three-fourths water and one-fourth rock or a mini-Neptune with an extensive, gaseous atmosphere.

University of Hawaii astronomer Christoph Baranec supplied confirming data with an instrument called Robo-AO, mounted on the Palomar 1.5-meter telescope in California. Former UH graduate student Brendan Bowler, now a postdoctoral fellow at Caltech, provided additional confirming observations using the Keck II telescope on Mauna Kea, according to a release Thursday from the UH Institute for Astronomy.

The Kepler spacecraft looks for planets that transit, or cross in front of, their star as seen from Earth. During the transit, the star’s light dims slightly.

The smaller the planet, the weaker the dimming, so brightness measurements must be extremely precise. To enable that precision, the spacecraft must stay steady.

Kepler’s primary mission came to an end in May 2013 when the second of four reaction wheels used to stabilize the spacecraft failed. Without at least three functioning reaction wheels, Kepler couldn’t be pointed accurately.

Rather than give up, a team of scientists and engineers developed a strategy to use pressure from sunlight as a virtual reaction wheel to help control the spacecraft.

"Like a phoenix rising from the ashes, Kepler has been reborn and is continuing to make discoveries," said Andrew Vanderburg of the Harvard-Smithsonian Center for Astrophysics in a statement. "Even better, the planet it found is ripe for follow-up studies."

Vanderburg is the lead author of a research paper on the discovery accepted for publication in the Astrophysical Journal.

Kepler’s second life, dubbed K2, promises not only to continue the search for other worlds but also introduce new opportunities to observe star clusters, galaxies and supernovae, scientists say.

Due to Kepler’s reduced pointing capabilities, extracting useful data requires sophisticated computer analysis. Vanderburg and his colleagues developed specialized software to correct for spacecraft movements, achieving about half the photometric precision of the original Kepler mission.

Kepler’s new life began with a nine-day test in February. When Vanderburg and his colleagues analyzed that data, they found that Kepler had detected a single planetary transit.

The close-in planet circles its star once every 9.1 days at a distance of 8.4 million miles. Its host star is a type K orange dwarf slightly smaller and cooler than the sun.

The system is 180 light-years from Earth in the constellation Pisces.

Since the host star is relatively bright and nearby, follow-up studies will be easier to conduct than for many Kepler planets orbiting fainter, more distant stars, said co-author John Johnson, a Harvard astronomer and former postdoctoral fellow at UH.

"HIP 116454b will be a top target for telescopes on the ground and in space," he predicted.