Astronomers Make Thrilling New Planet Discovery Near our Solar System

Astronomers have identified a new exoplanet orbiting Barnard’s star, the closest individual star to our solar system, situated just six light-years away.

This newly discovered planet, named Barnard b, is a small, rocky world with at least half the mass of Venus and completes an orbit around its star in just three Earth days. This breakthrough is the result of five years of meticulous observations by a team using state-of-the-art telescopes, shedding new light on the planets in our immediate cosmic vicinity.

Discovery of Barnard b

The discovery of Barnard b is a culmination of years of research and technological advancements. Using the Very Large Telescope (VLT) located at the European Southern Observatory (ESO) in Chile, astronomers were able to detect the planet’s faint gravitational signal through a method called radial velocity, which measures the wobble in the star caused by the planet’s gravitational pull. The ESPRESSO instrument on the VLT was crucial in detecting Barnard b’s signal, which was subsequently verified with additional data from other exoplanet-hunting tools, including HARPS (High Accuracy Radial Velocity Planet Searcher) at La Silla Observatory and CARMENES in Spain.

This discovery marks a significant moment in the search for exoplanets around Barnard’s star. Despite an earlier detection attempt in 2018, which hinted at a planet in this system, astronomers were not able to confirm it until now. Jonay González Hernández, the lead author of the study from the Instituto de Astrofísica de Canarias, said, “Even if it took a long time, we were always confident that we could find something.” After years of refining their methods and gathering data, the team has finally confirmed Barnard b’s existence, providing strong evidence that the nearest single star to our Sun hosts a planetary system.

Barnard’s star, located in the constellation Ophiuchus, has long been a primary target for astronomers searching for nearby exoplanets. As the second-closest star system to Earth after the Alpha Centauri system, Barnard’s star presents a unique opportunity for studying the formation and characteristics of planets around red dwarf stars—a type of star that is smaller and cooler than the Sun. Red dwarfs are known to host smaller, rocky planets, making them ideal for detecting low-mass exoplanets like Barnard b.

Characteristics of Barnard b

Barnard b is particularly intriguing because of its low mass and close orbit around its star. The planet orbits Barnard’s star at a distance 20 times closer than Mercury orbits the Sun, completing a full orbit in just 3.15 Earth days. Despite orbiting a cooler star, Barnard b has a surface temperature of approximately 125°C (257°F), making it too hot to support liquid water. González Hernández explained, “Even if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.” This insight rules out the possibility of the planet being habitable, but it provides valuable data on the diversity of planetary systems in our cosmic neighborhood.

What makes Barnard b stand out is its sub-Earth mass, making it one of the smallest exoplanets discovered to date. With at least half the mass of Venus, Barnard b is part of a growing list of low-mass planets found around red dwarfs. Planets like Barnard b are particularly valuable for research because they offer insights into how planets form and evolve around stars that differ significantly from our own Sun. Red dwarfs, which are more abundant in the universe than stars like the Sun, often host rocky planets that could provide new clues about planetary formation.

Barnard’s star, a red dwarf, emits far less light and heat than the Sun, but because Barnard b orbits so close to it, the planet’s temperature remains high. This discovery highlights the challenges of finding habitable planets around stars that are cooler than our Sun. While Barnard b lies well outside the habitable zone, where liquid water could exist, its discovery opens the door to the possibility of finding other planets in this system that might be in more temperate orbits.

Potential for More Discoveries

In addition to Barnard b, the research team has identified three more potential exoplanets orbiting Barnard’s star. While these planets have not yet been confirmed, preliminary signals suggest that the Barnard system could host multiple planets. The team is continuing their observations using the ESPRESSO instrument, which is capable of detecting even smaller planets and confirming the presence of additional worlds in the system. As Alejandro Suárez Mascareño, co-author of the study, explained, “We now need to continue observing this star to confirm the other candidate signals.”

The possibility of more planets orbiting Barnard’s star is exciting because it suggests that multi-planet systems may be more common than previously thought, even around nearby stars. Barnard b joins a growing list of low-mass planets discovered in our cosmic neighborhood, including Proxima b and Proxima d, both of which orbit Proxima Centauri, the closest star to the Sun. These discoveries indicate that our solar system may be surrounded by a rich diversity of planetary systems, each with its own unique characteristics.

The discovery of Barnard b and the potential for additional planets around Barnard’s star also demonstrates the power of modern astronomical instruments like ESPRESSO and HARPS. These tools are allowing astronomers to detect smaller and more distant planets than ever before, helping to build a more complete picture of the exoplanet population in our galaxy.