Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered an exoplanet orbiting Barnard’s star, the closest single star to our Sun. On this newly discovered exoplanet, which has at least half the mass of Venus, a year lasts just over three Earth days. The team’s observations also hint at the existence of three more exoplanet candidates, in various orbits around the star.
Located just six light-years away, Barnard’s star is the second-closest stellar system — after Alpha Centauri’s three-star group — and the closest individual star to us. Owing to its proximity, it is a primary target in the search for Earth-like exoplanets. Despite a promising detection back in 2018, no planet orbiting Barnard’s star had been confirmed until now.
The discovery of this new exoplanet — announced in a paper published today in the journal Astronomy & Astrophysics — is the result of observations made over the last five years with ESO’s VLT, located at Paranal Observatory in Chile. “Even if it took a long time, we were always confident that we could find something,” says Jonay González Hernández, a researcher at the Instituto de Astrofísica de Canarias in Spain, and lead author of the paper. The team were looking for signals from possible exoplanets within the habitable or temperate zone of Barnard’s star — the range where liquid water can exist on the planet’s surface. Red dwarfs like Barnard’s star are often targeted by astronomers since low-mass rocky planets are easier to detect there than around larger Sun-like stars.
Barnard b, as the newly discovered exoplanet is called, is twenty times closer to Barnard’s star than Mercury is to the Sun. It orbits its star in 3.15 Earth days and has a surface temperature of around 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 if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.”
About ESO
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. ESO provides state-of-the-art research facilities to astronomers and is supported by Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. Several other countries have expressed an interest in membership.
Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered an exoplanet orbiting Barnard’s star, the closest single star to our Sun. On this newly discovered exoplanet, which has at least half the mass of Venus, a year lasts just over three Earth days. The team’s observations also hint at the existence […]
