Barnard's Star is the closest single star system to Earth, located less than 6 light-years away, and hosts four confirmed exoplanets discovered between 2024 and 2025.
These exoplanets have masses between Earth and Mars but are likely uninhabitable due to high levels of periclase (magnesium oxide) that prevent water storage.
The planets orbit extremely close to their star (1% to 4% of Earth-Sun distance), are tidally locked, and lost their atmospheres after about 2 billion years due to stellar radiation.
Despite instability risks, the three inner planets maintain orbital resonance (9:12:16) which stabilizes the system.
The research, published in Monthly Notices of the Royal Astronomical Society, links stellar and planetary composition to assess habitability, aiding future missions like PLATO.