Chilean astronomers discover exoplanet similar to Neptune

A planet smaller than Neptune, very dense and massive, orbiting a young star located 125 light years away, is the discovery made by a team of national astronomers.

“This planet is on the edge of the Neptunian desert (very close to its star, where planets of this size cannot exist), and it is the youngest in that regime, which makes it an essential discovery.”explained José Vinés, PhD student in Astronomy at the University of Chile and first author of the paper.

With an age of 300 million years, and located in the HD 18599 system, this world is an amazing discovery. “The discoveries of young planets are essential to understand the processes of evolution and are very rare”Vines adds.

The investigation began in 2010, when the first data were taken by the WASP (Wide Angle Search for Planets) instrument, located in South Africa, in a planet search campaign. “Although they didn’t find the planet candidate, these observations were important in determining the star’s rotational period.”Vines explains. Subsequently, radial velocity observations were made with HARPS (High Accuracy Radial Velocity Planet Searcher) at ESO’s La Silla observatory in northern Chile, starting in 2014.

The data allowed to detect the transit of this object. In this way, a decisive follow-up began, essential to confirm the object and measure its mass. James Jenkins, CATA researcher, indicated that “Young stars present problems for the discovery and characterization of small planets, since they are very active bodies. This adds noise to our measurements, confounding the algorithms we use for their discovery.”

But it would not be until 2018 when Chilean astronomers began their research using MINERVA (Miniature Exoplanet Radial Velocity Array) located at Mount Kent Observatory in Australia. With these data the team found this “unusual planet”.

The name of the investigation is “A mini dense Neptune orbiting the young star HD 18599” and appeared in the latest issue of the Monthly Notices of the Royal Astronomical Society.