Thanks to ESO’s VLT, astronomers have discovered a planet orbiting Barnard’s Star, the closest single star to the Sun
Using the VLT (Very Large Telescope) of the ESO (European Southern Observatory), some astronomers have discovered a planet orbiting Barnard’s star, the single star closest to the Sun. On this newly discovered exoplanet, which has a mass equal at least half that of Venus, a year lasts just over three Earth days. The team’s observations also suggest the existence of three other exoplanet candidates, in different orbits around the star. Located just six light-years away, Barnard’s Star is the second star system, after the three-star group of Alpha Centauri, and the closest single star to us. Due to its proximity, it is a prime target in the search for Earth-like exoplanets. Despite a promising revelation in 2018, no planets had so far been confirmed orbiting Barnard’s Star.
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5 years of observations
The discovery of this new planet, announced in an article published today in the magazine Astronomy & Astrophysicsis the result of observations carried out over the last five years with the from ESO, located at the Paranal Observatory in Chile. The team was looking for signals from possible exoplanets within Barnard’s star’s habitable or temperate zone, the range in which water can be liquid on the surface of planet. Red dwarfs like Barnard’s Star are often considered by astronomers as there i rocky planets of low mass are easier to detect than around larger stars, similar to the Sun.
The planet
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 the star in 3.15 Earth days and has a surface temperature of about 125°C. For the observations, the working group used ESPRESSO, a very precise instrument designed to measure the oscillation of a star caused by the gravitational attraction of one or more planets orbiting around it. The results obtained from these observations were confirmed by data from other instruments specialized in exoplanet hunting: HARPS at ESO’s La Silla Observatory, HARPS-N and CARMENES. The new data, however, does not support the existence of the exoplanet reported in 2018.
In addition to the confirmed planet, the international team also found hints of three other exoplanet candidates orbiting the same star. Further observations with ESPRESSO will be needed for confirmation. ESO’s Extremely Large Telescope (ELT), currently under construction, is set to transform the field of exoplanet research. The ELT’s ANDES instrument will make it possible to detect more and more of these small rocky planets in the temperate zone around nearby stars, beyond the reach of current telescopes, and to study the composition of their atmospheres.
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