An international team of astronomers has located a planet orbiting Barnard’s Star, located just six light years away. In this new world, whose mass is less than that of the Earth, a year lasts a little more than three Earth days. After the Alpha Centauri cluster of three stars, Barnard’s Star is the second closest star system to us, just six light years away, in addition to being the closest individual star.
Due to its proximity, it constitutes a privileged target in the search for exoplanets similar to Earth. Despite a promising detection in 2018, no planet has been confirmed orbiting Barnard’s Star to date, but a team of astronomers has found it.
Your name, Barnard b.which has at least half the mass of Venus. The discovery of this new world is announced this week in the magazine Astronomy and astrophysics.
“Even though it took us a long time, we were always sure we could find something”, declared Jonay González Hernándezresearcher at the Institute of Astrophysics of the Canary Islands (IAC) and lead author of the article. The team was looking for signs of possible exoplanets in the habitable or temperate zone of Barnard’s star, the area where liquid water can exist on the planet’s surface.
The Barnard exoplanet has at least half the mass of Venus
Small planet in a red dwarf
The astronomical community often focuses on the study of red dwarfs (like Barnard’s Star) because low-mass rocky planets are easier to detect in their environment, which is more complex to do if we are talking about larger stars, like the Sun. Barnard b is twenty times closer to Barnard’s star than Mercury. of the Sun. It orbits its star in 3.15 Earth days and has a surface temperature of approximately 125°C.
“Barnard b is one of the lowest mass exoplanets known and one of the few known with a mass less than that of Earth. But the planet is too close to the host star, closer than the habitable zone,” explains González Hernández. “Even though the star is about 2,500 degrees cooler than our Sun, it is too hot to maintain liquid water on the planet’s surface,” he adds.
Support VLT and other instruments
For their observations, the team used ESPRESSO, a high-precision instrument designed to measure the wobble of a star caused by the gravitational pull of one or more orbiting planets. It is installed in the Very Large Telescope (VLT) from the European Southern Observatory (ESO), to the Paranal Observatory, in Chile.
The results obtained from these observations were confirmed by data from other instruments, also specialized in the search for exoplanets: HARPS, from the La Silla Observatory of ESO, HARPS-N and CARMENES. However, the new data does not confirm the existence of the exoplanet reported in 2018.
This small world is 20 times closer to its star than Mercury is to the Sun, and orbits it in 3.15 Earth days.
In addition to the confirmed planet, the international team also found indications of the presence of three other candidate exoplanets orbiting the same star. However, these candidates will require additional observations with ESPRESSO to be confirmed.
“We must now continue to observe this star to confirm other signals from possible candidates”, says the co-author Alejandro Suarez Mascarenoalso a researcher at the IAC, “but the discovery of this planet, along with other previous discoveries such as Proxima b and d, show that our cosmic backyard is full of low-mass planets.”
Signs of three other exoplanet candidates orbiting the same star have also been discovered.
ESO’s Extremely Large Telescope (ELT), currently under construction, is poised to transform the field of exoplanet research. He ANDES Instrument The ELT will allow the scientific community to detect more of these small, rocky planets in the temperate zone around nearby stars, beyond the reach of current telescopes, and allow them to study the composition of their atmospheres.
