Barnard’s Star has fascinated astronomers for decades. At just six light-years away, it is the second-closest single star to our own Sun. Now, two separate research teams have found solid evidence that four tiny planets—each less than half the mass of Earth—circle this nearby star at incredibly close distances.
The findings, published in the The Astrophysical Journal Letters, come from observations by two highly specialized instruments: MAROON-X, located on the Gemini-North telescope in Hawaiʻi, and ESPRESSO, on the Very Large Telescope in Chile. These instruments detect minute “wobbles” in the star’s motion—caused by the gravitational pull of orbiting planets.
“It’s a really exciting find—Barnard’s Star is our cosmic neighbor, and yet we know so little about it,” said University of Chicago Ph.D. student Ritvik Basant, first author of the study. “It’s signaling a breakthrough with the precision of these new instruments.”
Barnard’s Star has long been a target for planet-hunters because of its proximity and its status as a single red dwarf star. Many previous attempts to detect planets there hinted at something, but never reached conclusive proof.
Four confirmed planets
In late 2024, astronomers using ESPRESSO published strong evidence in the Journal of Astronomy & Astrophysics of at least one planet around Barnard’s Star and possible signs of more. This latest study adds onto that, observing the star on 112 different nights over three years and confirming three planets beyond question. When researchers combined those results with the ESPRESSO data, they found enough proof to “nail down” a fourth planet.
All four planets are incredibly close to their host star—completing their orbits in only a few days. Because they are so near to Barnard’s Star — even though it is relatively cool — these worlds are likely too hot for life as we know it. The new planets represent some of the smallest and most challenging planets ever detected by measuring a star’s wobble.
Planets are usually too dim and close to their stars for scientists to photograph directly. Instead, instruments like MAROON-X and ESPRESSO look for shifts in the star’s light. As a planet orbits, its slight gravitational pull makes the star move back and forth, changing the star’s spectrum in a very small but detectable way. By tracking these changes over time, scientists can determine how many planets there are and estimate their masses.
But how do astronomers know for sure these planets are legit? Groups studying the star have announced evidence suggesting planets around Barnard’s Star before, only for them to be disproven later.
“We observed at different times of night on different days,” Basant said. “(The other researchers) are in Chile; we’re in Hawaiʻi. Our teams didn’t coordinate at all, which gives us a lot of assurance these aren’t illusions in the data.”
Because Barnard’s Star and its newly confirmed planets are so close, future observations might uncover more about these small worlds, such as their atmospheric conditions—if they have any atmosphere at all.
The team also looked for planets in the “habitable zone,” where the star’s warmth might allow liquid water to exist. So far, they see no evidence of planets larger than half of Earth’s mass. That does not rule out smaller worlds entirely, but spotting them would require even more precise instruments or new techniques.
This discovery adds Barnard’s Star to a growing list of red dwarf stars with multiple small planets orbiting at close range. These compact systems are important to astronomers trying to understand how planets form and evolve.
“We found something that humanity will hopefully know forever,” said Jacob Bean of the University of Chicago, who helped develop MAROON-X. “That sense of discovery is incredible.”
