An international team, led by researchers from the Institute of Astrophysics and Space Sciences (IA), has found two “rare supermercuries” in the same star system that could provide “clues” to the formation of planets like Mercury.
In a statement, the AI clarifies this Tuesday that the discovery of these two exoplanets in the same solar system occurred during the observation of the HD 23472 system with the ESPRESSO spectrograph, installed on the Very Large Telescope (VLT) of the European Southern Observatory. (ESO), in Chile.
The research, published in the scientific journal Astronomy & Astrophysics, aimed to characterize the composition of small planets, understand how the composition can change the location and temperature of the planet, and how it relates to the properties of the parent star.
Quoted in the statement, the researcher who led the study, Susana Barros, clarifies that the team wanted to “study the transition between having or not having an atmosphere, which may be related to the evaporation caused by the irradiation of the star.”
“The team found that the system has three super-Earths with a significant atmosphere and, surprisingly, two super-mercuries that are also the closest planets to the star”, reveals the researcher from the Department of Physics and Astronomy of the Faculty of Sciences of the University. of Porto (FCUP).
The difference between an Earth-type planet and a Mercury-type planet is that it has a higher percentage of iron and a comparatively larger iron core, both of which are “very rare.”
Only eight supermercuries are known so far, including the two now discovered, the AI highlights.
The institute also clarifies that of the five exoplanets of the HD 23472 system, three have masses smaller than Earth, being “lighter” exoplanets and whose masses were measured using the “radial velocity method, something that has only been possible thanks to to the precision of the ESPRESSO spectrograph”.
“The presence of not one, but two supermercuries, left the team wanting to dig deeper into the subject,” emphasizes the AI, noting that the reasons why the planet Mercury has a relatively larger core and mantle are unknown. thicker. .smaller than other planets.
“For the first time we have discovered a star system with two supermercuries. This gives us clues about the formation of these planets, which can help us rule out some hypotheses”, underlines Susana Barros, pointing out that we still do not know how these types of planets are formed.
“It seems to be related to the composition of the parent star,” he adds, noting that the system the research focused on may help uncover the reasons.
Also quoted in the statement, Olivier Demangeon, an AI researcher who was also involved in the study, adds that understanding how these two exoplanets formed “will require better compositional characterization.”
“Since these planets have smaller diameters than Earth, current instruments do not have sufficient resolution to measure the composition of the surface, or even the existence of a potential atmosphere”, points out the researcher, noting, however, that the future Extremely Large Telescope (ELT) and its first-generation spectrograph, called ANDES, will have the necessary sensitivity and precision.
Source: TSF
