Free Astronomy Magazine May-June 2025

5 MAY-JUNE 2025 ASTRO PUBLISHING One such effort was led by Jacob Bean from the University of Chicago, whose team created an instrument called MAROON-X, which is de- signed specifically to search for dis- tant planets around red dwarf stars. MAROON-X is mounted on the Gemini North telescope, one half of the International Gemini Obser- vatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab. MAROON-X hunts for exoplanets using the radial velocity technique, meaning it detects the subtle back and forth wobble of a star as its ex- oplanets gravitationally tug on it, which causes the light emitted by the star to shift ever so slightly in wavelength. The powerful instru- ment measures these small shifts in light so precisely that it can even tease apart the number and masses of the planets that must be circling the star to have the observed effect. After rigorously calibrating and an- alyzing data taken during 112 nights over a period of three years, the team found solid evidence for three exoplanets around Barnard’s Star, two of which were previously classi- fied as candidates. The team also combined data from MAROON-X with data from a 2024 study done with the ESPRESSO instrument at the European Southern Observa- tory’s Very Large Telescope in Chile to confirm the existence of a fourth planet, elevating it as well from can- didate to bona fide exoplanet. “It’s a really exciting find — Barnard’s Star is our cosmic neighbor, and yet we know so little about it,” says Ritvik Basant, PhD student at the University of Chicago and first au-