In a groundbreaking discovery, astronomers have identified an exoplanet orbiting Barnard's Star, the closest solitary star to our Solar System, located approximately 6 light years away. Dubbed Barnard b, this planet is somewhat smaller than Venus, marking a significant addition to our understanding of nearby stellar systems.

Barnard's Star, a red dwarf, hosts its newly discovered companion at a distance just 2.9 million kilometers away – only 5% of the distance between Mercury and the Sun. Despite this proximity, Barnard b completes an orbit in merely 3.15 Earth days. This close orbit results in a surface temperature of approximately 125°C, ruling out the possibility of liquid water on its surface.

The discovery was made using the ESPRESSO spectrograph on the Very Large Telescope (VLT) at the European Southern Observatory in Chile. Led by Jonay González Hernández from the Instituto de Astrofísica de Canarias (IAC), the international research team has been meticulously studying Barnard's Star since 2018, hoping to find signs of planets within its habitable zone.

Even though the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface, explains González Hernández. His team has identified Barnard b as one of the lowest-mass exoplanets known, and one of the few with a mass less than that of Earth, noting its proximity to the star excludes it from being within the habitable zone.

This finding is of great significance not only because of the planet's proximity but also because Barnard's Star lies in our cosmic backyard, a mere 6 light years away. With three additional candidate exoplanets potentially orbiting Barnard's Star, the region presents a fertile ground for further investigation and possibly more discoveries of rocky planets similar to Earth.

We now need to continue observing this star to confirm the other candidate signals, says Alejandro Suárez Mascareño, another researcher at the IAC and co-author of the study. The detection of Barnard b, along with previous discoveries such as Proxima b and d, underscores that our solar neighborhood is densely populated with low-mass planets.

In addition to Barnard b, astronomers have detected three more possible planets around Barnard's Star which, if confirmed, would add to the growing list of nearby exoplanets. This discovery suggests that the area around Barnard's Star could be abundant in low-mass exoplanets. The team has utilized high-precision instruments to study the variations in the star's spectrum created by the gravitational pull of orbiting planets. These observations were corroborated using other specialized instruments like HARPS in the ESO's La Silla Observatory and CARMENES in the Calar Alto Observatory in Almería, Spain.

The search for planets in the region continues, as the research team aims to verify the existence of these additional candidates. Now we have to keep observing this star to confirm the signals of the other candidates, asserts Suárez Mascareño. The eventual confirmation of these planets could significantly advance our understanding of exoplanetary systems and the diversity of planets within them.

This revelation aligns with other similar discoveries in the vicinity of our solar system. Red dwarf stars like Barnard's and Proxima Centauri, the latter located only 4.24 light years away, have been found to host multiple exoplanets. Another system, TRAPPIST-1, situated about 40 light years from the Sun, boasts seven Earth-sized planets, three of which reside in the star's habitable zone.

These findings highlight the dynamic and diverse nature of our cosmic neighborhood. Astronomers believe that with forthcoming advanced telescopes such as the Extremely Large Telescope (ELT) currently under construction in Chile, these kinds of discoveries will become more frequent. These instruments will enable researchers to further investigate and potentially confirm the presence of additional exoplanets, unlocking new possibilities in the hunt for habitable worlds.

González Hernández and his colleagues remain committed to this search, driven by the prospect of uncovering more about these nearby planets and the conditions under which they exist. Their work continues to inspire interest and optimism within the scientific community and beyond, as we edge closer to understanding the complexities of planetary systems around red dwarf stars.