SANTA CRUZ DE TENERIFE, Oct. 1 (EUROPA PRESS) –
The closest isolated star to the Sun is called Barnard and a team of researchers, led by the Institute of Astrophysics of the Canary Islands (IAC), has just detected that it has a ‘sub-earth’ orbiting it. The exoplanet found, named Barnard b, has at least half the mass of Venus and rotates rapidly around its star, so that a year lasts just over three Earth days.
The new exoplanet is seventeen times closer to Barnard’s star than Mercury is to the Sun and has a surface temperature of around 125°C, which prevents it from having liquid water on its surface.
This discovery led by the IAC, in collaboration with different international centers, has been produced with images from the ESPRESSO spectrograph installed on the Very Large Telescope (VLT) of the European Southern Observatory (ESO), located at the Paranal Observatory in Chile, and has been published by the journal Astronomy & Astrophysics.
The same work also points to the existence of three other candidate objects for exoplanets orbiting this same star, which confirms the trend that the solar neighborhood becomes the place with the best chance of finding an Earth that harbors life in solar systems similar to ours.
After Alpha Centauri, Barnard is the closest star system to the Solar System and is located just 6 light years from Earth. This proximity, and the fact that it is a red dwarf type star, has meant that scientists have been studying it since 2018.
The main author of the article and IAC researcher Jonay González Hernández explains that “although it has taken us many years, we were convinced that in this system so relevant due to its proximity to the Sun, the circumstances were met to find a planet similar to Earth.”
The research team’s efforts in recent years focused on searching for signs of possible exoplanets within the habitable zone or temperate zone of Barnard’s star, that is, the area in which liquid water may exist on the surface of the planet.
In this sense, González Hernández explains that “Barnard b is one of the lowest mass exoplanets known and one of the few with a mass lower than that of the Earth. However, the planet is too close to the host star, closer than the habitable zone” and adds that, “although the star is about 2,500 degrees colder than our Sun, on the planet’s surface it is too hot to maintain liquid water on its surface.”
A FINDING WITH THE HELP OF ESPRESSO
To make this discovery with the VLT, the team used the ESPRESSO (Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations) instrument, an ultra-stable, high-resolution spectrograph that aims to search for and characterize Earth-like planets like the study. of the variation of the fundamental astrophysical constants and whose project was co-led by the IAC, which participated in its design and construction.
The ESPRESSO instrument made it possible to study the variation of the star caused by the gravitational attraction of one or several planets in orbit. Subsequently, these results were confirmed with data from other instruments, also specialized in exoplanet hunting, such as HARPS at ESO’s La Silla Observatory and CARMENES at the Calar Alto Observatory (Almería).
The research team continues to study the three candidate exoplanet objects in the environment of this star to see if they are finally confirmed as exoplanets. “Now we have to continue observing this star to confirm the signals of the other candidates,” says Alejandro Suárez Mascareño, a researcher also at the Institute of Astrophysics of the Canary Islands and co-author of the study. “The discovery of this planet, along with previous discoveries such as Proxima b and d, demonstrates that our ‘cosmic backyard’ is full of low-mass planets.”
This work has had the participation of other IAC researchers such as Rafael Rebolo, Atanas Stefanov, Nicola Nari, Vera Passegger, Carlos Allende Prieto, Ricardo Génova and Enric Pallé.
