Astronomers have managed to measure the masses, densities, and orbital parameters of the planets in two multiple planetary systems: K2-32, a miniature version of our Solar System with four planets, and K2-233, with the two youngest rocky exoplanets known to date.

The study carried out by the Center for Astrobiology (CAB, CSIC-INTA) and the European Southern Observatory (ESO) will allow scientists to investigate the early phases of rocky planets such as Earth and deepen the analysis of extrasolar planets, one of the great unknowns of astrobiology.

For this area, it is important to obtain accurate information on the atmospheric properties and internal structure of the 4,000+ exoplanets that have been discovered. In order to do so, it is necessary to know the mass and size of each planet with precision.


So, the results of the study published by Astronomy & Astrophysics show that the K2-32 planetary system is a compact and reduced version of the Solar System, with a rocky planet in the inner zone of the system (K2-32 e), followed by a gas giant with the mass of Neptune (K2-32 b), and two mini-Neptune-type planets in the outermost zone (K2-32 c and K2-32 d), all of them within an orbit twice as small as that of Mercury.

In this way, K2-32 is one of the few multi-planetary systems with four or more known planets where all the masses and radio of their planets are known.

The second system, K2-233, consists of two Earth-sized, rocky inner planets (K2-233 b and K2-233 c) and a mini-Neptune-type outer planet (K2-233 d).

“In the case of K2-233, we measured for the first time the mass of two rocky planets in a young star, about 600 million years old. They are the youngest rocky planets known to date, both with densities similar to Earth. This opens the door for the first time to the study of the earliest history of planets like our own,” explained Jorge Lillo Box, postdoctoral researcher from the María de Maeztu program at the CAB and lead author of the study.

“There are very few planets whose ages are known in a sufficiently precise way and this fact is very important to confront the study data with theoretical models and to understand the context of the evolution of its properties,” added David Barrado, researcher at the CAB and co-author of the study.

With information from the EFE agency.