Astronomers have announced the confirmation of the first exoplanet candidate identified by NASA's Kepler Space Telescope, which was launched 10 years ago.

Kepler Space Mission

Since its launch in March 2009, the Kepler Space Telescope has already discovered thousands of exoplanets using the transit method, a technique used for detecting distant planets by measuring the dips in a star's brightness as a planet passes between it and the Earth.

Other phenomena, however, can mimic planetary transits, so while Kepler's data can reveal potential planet candidates, further analysis is needed to confirm these worlds as genuine planets.

Kepler-1658 b: First Exoplanet Candidate Discovered By Kepler

The very first exoplanet candidate discovered by Kepler is an object known as Kepler-1658 b, but it took a long time before scientists were able to confirm it as a planet.

Scientists were initially wrong about the size of the planet's host star, so the sizes of the star and Kepler-1658 b was greatly underestimated. Astronomers who re-analyzed Kepler's host star fortunately spotted the discrepancies.

"Our new analysis, which uses stellar sound waves observed in the Kepler data to characterize the host star, demonstrated that the star is in fact three times larger than previously thought. This in turn means that the planet is three times larger, revealing that Kepler-1658 b is actually a hot Jupiter-like planet," said University of Hawaiʻi graduate student Ashley Chontos.

Chontos and colleagues then alerted Dave Latham, a senior astronomer at the Smithsonian Astrophysical Observatory, who collected the needed spectroscopic data that eventually revealed Kepler-1658 b is indeed a planet.

Kepler-1658

Kepler-1658 b's host star Kepler-1658 is 50 percent more massive and three times larger than the sun. Kepler-1658 b orbits around it at a distance of twice the star's diameter, making the newly confirmed exoplanet one of the closest-in planets around a more evolved star.

"Kepler-1658 joins a small population of evolved hosts with short-period (≤100 days) planets and is now the closest known planet in terms of orbital period to an evolved star," the researchers wrote in their study.

If a person is to see Kepler-1658 on the planet, the star would appear 60 times larger in diameter than the sun as seen from Earth.

The findings were presented at the fifth Kepler/K2 Science Conference held from March 4 to 8 in Glendale, California.