Astronomers have found three super-Earths orbiting around a cool star called LP 415-17. They used data from the NASA Kepler spacecraft’s reborn K2 mission.
LP 415-17 is also known as EPIC 210897587 and 2MASS 04215245+2121131. It is a mid-late type K-dwarf star which lies approximately 267 light-years from Earth.
The star has a radius about 58% that of our Sun, a mass 65% that of the Sun, and is home to at least three massive planets: LP 415-17b, c and d.
Researchers detected the planets through the transit method. Scientists indicate a possible transit across the star’s face by an object if there was a dip in the intensity.
However, Kepler has discovered more than 2,300 exoplanets to date. In 2013 the spacecraft lost its two reaction wheel. However, engineers repurposed it as K2 to perform high-precision photometry of selected fields in the ecliptic. Since then, the revived Kepler telescope has found nearly 200 extrasolar worlds.
So, Dr. Francisco Javier de Cos Juez from the University of Oviedo and colleagues relied on data from K2’s Campaign 13 (took place between March 08th and May 27th, 2017) to determine the sizes, masses, and orbits of these planets.
LP 415-17b, c and d have radii 1.8, 2.6 and 1.9 times that of Earth, respectively, and orbit their parent star with periods of 6.34, 13.85 and 40.72 days.
LP 415-17d is the smallest and farthest planet. It lies close to the inner edge of the habitable zone and has a radius of 0.18 AU.
Scientists classified the newly detected planets as super-Earths. That’s because they have masses higher than Earth’s but lower than that of solar system’s gas giants.
According to the team, the LP 415-17 system is a good observational target for future facilities such as the NASA/ESA/CSA James Webb Space Telescope.
The researchers concluded that the newly confirmed planets could advance our understanding of the formation and dynamical evolution of super-Earth systems in the rocky – gaseous threshold.
“This system is suitable to improve our understanding of the formation and dynamical evolution of super-Earth systems in the rocky-gaseous threshold, their atmospheres, internal structure, composition, and interactions with host stars,” Dr. de Cos Juez and co-authors said.
Thumbnail image: Artist’s impression of the trio of super-Earth exoplanets. Credit: ESO.