Mini-Earth exoplanets orbiting Barnard’s Star animation. Video via NOIRLabAstro.
- Barnard’s Star is a red dwarf star. It is the closest single star to our solar system, only 6 light-years away.
- Astronomers previously confirmed one planet orbiting Barnard’s Star, smaller and less massive than Earth.
- Now a total of four known planets have been confirmed. All are “mini-Earths,” only 20% to 30% the mass of Earth.
4 new mini-Earth exoplanets nearby
Last October, astronomers announced the discovery of the first known planet orbiting Barnard’s Star, the closest single star to our solar system. On March 11, 2025, an international team of astronomers said it has confirmed three more, for a total of four planets. The researchers said all four planets are smaller and less massive than Earth. They used the Gemini North telescope in Hawaii and previous data from the Very Large Telescope (VLT) in Chile to make the discovery.
The researchers published the exciting peer-reviewed findings in The Astrophysical Journal Letters on March 11, 2025.
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Does Barnard’s Star have planets?
Barnard’s Star is a red dwarf, the most common type of star in our Milky Way galaxy. In fact, most of the more than 5,000 exoplanets astronomers have so far confirmed around other stars orbit red dwarfs. So, does Barnard’s Star have planets, too? It seems reasonable, given the numerous other red dwarfs with planets.
Previous searches hinted at planets around Barnard’s Star, but they remained unconfirmed. Then, the study from last year using the Very Large Telescope finally confirmed one planet, about half the mass of Venus.
4 mini-Earth exoplanets for Barnard’s Star
Now we know that Barnard’s Star has at least four planets! Jacob Bean from the University of Chicago led the new search. They used a new instrument called MAROON-X, attached to the Gemini North telescope. It was designed specifically to look for planets around red dwarfs. MAROON-X uses the radial velocity method in its search. That means it detects the tiny wobbles of a star due to planets tugging on it with their gravity.
Overall, the required observations took time: 112 nights over three years altogether. But it paid off in spades. The astronomers were able to confirm three more planets around Barnard’s Star plus the previous planet for a total of four. Lead author Ritvik Basant at the University of Chicago said:
It’s a really exciting find, Barnard’s Star is our cosmic neighbor, and yet we know so little about it. It’s signaling a breakthrough with the precision of these new instruments from previous generations.
All four of the planets are smaller and less massive than Earth. They range from about 20% to 30% Earth’s mass. They are, therefore, most likely rocky. That aspect of them still needs to be further confirmed, however. In addition, the fourth planet is the least massive exoplanet found to date using the radial velocity method.
Confirmed at last! Following decades of disproven claims, four small exoplanets have been confirmed to orbit Barnard’s Star, the second-closest star system to Earth after Alpha Centauri. aasnova.org/2025/03/11/c… ??
— AAS Nova (@aasnova.org) 2025-03-11T17:11:46.022Z
Confidence in the data
The researchers are confident that these are real planets and no longer just candidates. Basant said:
We observed at different times of night on different days. They’re in Chile; we’re in Hawaii. Our teams didn’t coordinate with each other at all. That gives us a lot of assurance that these aren’t phantoms in the data.
The discovery is reminiscent of the planets around TRAPPIST-1, another red dwarf. That star has seven known rocky planets, all similar in size to Earth. Some of the those planets orbit in the star’s habitable zone, where temperatures could allow liquid water to exist.
Whether any of the Barnard’s Star planets could be potentially habitable is still unknown. But it will be interesting to see what else astronomers can find out about them!
Bottom line: Astronomers have confirmed four mini-Earth exoplanets orbiting Barnard’s Star, which is a red dwarf and the closest single star to our solar system.
Source: Four Sub-Earth Planets Orbiting Barnard’s Star from MAROON-X and ESPRESSO
Via NOIRLab
Read more: Barnard’s Star has 1 planet, maybe more, at last!
Read more: The enduring mystique of Barnard’s Star