Three 'super-Earth' exoplanets orbiting nearby star discovered

Kepler is the most prolific planet-hunting telescope. The

a

spacecraft has discovered more than 2,300 exoplanets to date. After the failure of its two reaction wheels in 2013, the mission was repurposed as K2 to perform high-precision photometry of selected fields in the ecliptic. Since then, the revived Kepler spacecraft has detected nearly 160 extrasolar worlds.

Now, a team of astronomers led by Joseph Rodriguez of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, reports the finding of three new exoplanets from the data provided by K2. The Kepler spacecraft observed GJ 9827 from December 2016 to March 2017, during its Campaign 12. These observations allowed the team to discover that this nearby late K-type dwarf star is orbited by three alien worlds. The newly found planets were classified as "super-Earths" as they have masses higher than Earth's but lower than that of Solar System's gas giants.

"In this paper, we present the discovery of three transiting planets orbiting the nearby star GJ 9827 using data from the K2 mission," the researchers wrote in the paper.

Located some 100 light years away from the Earth, GJ 9827 is a bright star of spectral type K6V. It has a radius of about 0.63 solar radii and is approximately 15 percent less massive than our Sun. The scientists found that the star is circled by three planets, designated GJ 9827 b, c and d, located about 0.02, 0.04 and 0.06 AU from the host respectively.

According to the paper, GJ 9827 b has a radius of 1.64 Earth radii but its precise mass remains uncertain. The researchers estimate that its mass should be between 3.5 and 4.26 Earth masses. The planet orbits its parent star in approximately 1.21 days and has an equilibrium temperature of 1,119 K.

Read more at: https://phys.org/news/2017-09-super-earth-exoplanets-orbiting-nearby-star.html#jCp