A planet smaller than Neptunevery dense and massive, orbiting a young star located 125 light years away, is the discovery of a team of astronomers from the University of Chile and the Diego Portales University.
“This planet is located 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”, José explains. Vinés, Ph.D. 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 a surprising discovery “The discoveries of young planets are essential to understand the processes of evolution and are very rare,” adds Vinés.
The beginnings of the research 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 did not find the candidate for a planet, these observations were important to determine the rotation period of the star”, explains Vinés. Radial velocity observations were subsequently made with HARPS (High Accuracy Radial Velocity Planet Searcher) at ESO’s La Silla observatory in northern Chile, starting in 2014.
Data from the Transiting Exoplanet Survey Satellite (TESS) made it possible 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, UDP astronomer and CATA researcher, stated: “Young stars present problems for the discovery and characterization of small planets, as 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. “I made observations of radial velocities with FEROS (Fiber-fed Extended Range Optical Spectrograph, from the La Silla observatory)”, indicates Vinés, who adds that “the next step will be to learn more about the characteristics of the planet, what the composition of its atmosphere”.
With these data the team found this “unusual planet”. The paper was co-written by José Vinés and James Jenkins, researcher at CATA and at the UDP Astronomy Center. Also collaborating: Zaira Berdiñas, who made her contributions while she was developing her postdoctorate in astronomy at the University of Chile; Maritza Soto of the University of Queen Mary in London; Matías Díaz Doctor in Astronomy U. de Chile and researcher at the Las Campanas Observatory; Douglas Alves from the University of Chile; and Pablo Peña from U. Diego Portales.
The name of the research is “A dense mini-Neptune orbiting the bright young star HD 18599” and it appeared in the latest issue of the journal Monthly Notices of the Royal Astronomical Society.