European Southern Observatory (ESO) has discovered a two super-earth planets.
Both planets orbit K2-18, a red-dwarf star located about 111 light years away in the constellation Leo.
When the planet K2-18b was first discovered in 2015, it was found to be orbiting within the star’s habitable zone, making it an ideal candidate to have liquid surface water, a key element in harbouring conditions for life as we know it.
The data set used by the researchers came from the High Accuracy Radial Velocity Planet Searcher (HARPS) using the ESO’s 3.6m telescope at La Silla Observatory, in Chile.
HARPS allows for measurements of radial velocities of stars, which can be affected by the presence of nearby planets, to be taken with the highest accuracy currently available. The instrument makes it possible to detect very small planets orbiting those stars.
In order to figure out whether K2-18b was a scaled-up version of Earth (mostly rock), or a scaled-down version of Neptune (mostly gas), researchers had to first figure out the planet’s mass, using radial velocity measurements taken with HARPS.