An international team of astronomers Barnard b, an exoplanet, has been discovered of at least half the mass of Venus which orbits Barnard’s star, the closest to the Sun. Scientists do not rule out that there are three other exoplanets in other orbits of the star.
Located just six light years away, Barnard is the fastest single star in the night sky and the second closest star system in the neighborhood, after the Alpha Centauri group. Due to its proximity, this celestial body is a main goal in the search for Earth-like exoplanetsalthough, since 2018, when a team of astronomers discovered a planet orbiting Barnard, no other had been discovered in its orbit.
That body found in 2018, a super-Earth three times the mass of the Earth and with an orbit of about 233 days, had characteristics that made life unviable. The new exoplanet, which has been discovered with the help of the Very Large Telescope (VLT), of the European Southern Observatory (ESO), in Chile, “is completely different” but equally inhospitable to harboring lifeas explained by Alejandro Suárez Mascareño, researcher at the Institute of Astrophysics of the Canary Islands (IAC) and co-author of the study.
Five years of research
The details of the new planet were published this Tuesday in an article in the magazine Astronomy & Astrophysics and are the result of observations made during the last five years. “Even if it took us a long time, we were always sure we could find something“, declared Jonay González Hernández, also an IAC researcher and main author of the article.
The team searched for signs of possible exoplanets within the habitable zone or temperate of Barnard’s Star, the range where liquid water can exist on the planet’s surface. Often, the astronomical community focuses on the study of red dwarfs (like Barnard) because low-mass rocky planets are easier to detect in their environment, something more complex to do if we are talking about larger stars, similar to the Sun.
The new exoplanet is twenty times closer to Barnard than Mercury is to the Sun, and “has a surface temperature of about 125 degrees and an orbital period of 3.15 Earth days,” Suárez Mascareño detailed. “Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of the Earth. But the planet is too close to the host star,” González Hernández highlighted, while stating that “even if the star were about 2,500 degrees cooler than the Sun, It’s too hot to hold liquid water on the surface of the planet.”
The study
To do this study, the team used ESPRESSO, a high-precision instrument that measures the wobble of a star caused by the gravitational pull of one or more orbiting planets. Astronomers take advantage of this effect to accurately measure changes in a star’s velocity due to an orbiting exoplanet. Barnard b’s discovery also has been confirmed by data from other instruments also specialized in the search for exoplanets: HARPS, at ESO’s La Silla Observatory, HARPS-N and CARMENES.
For its part, the new data calls into question the exoplanet found in 2018. “We have not been able to confirm its existence and, in fact, at this time the general consensus is that this exoplanet may not exist,” said Suárez Mascareño, who also considered that ““Barnard star could have up to three more exoplanets orbiting it.” “For now, we only have indications that we cannot confirm,” concluded the IAC researcher.
“The discovery of this planet, along with other previous discoveries such as Next byd, shows that our cosmic backyard is full of low-mass planets,” highlighted the researcher. To this end, ESO’s Extremely Large Telescope, currently under construction, will have the ANDES instrument that will allow the scientific community detect more of these small rocky planets in the temperate zone around nearby stars and study the composition of their atmospheres.
