Astronomers confirm planet's chemistry matches its star, aiding search for habitable worlds

Astronomers have found that ultra-hot Jupiter WASP-189b, 320 light-years away, has a magnesium-to-silicon ratio matching its host star, providing the first direct evidence supporting a key assumption about planet formation. An international team led by Arizona State University used the IGRINS spectrograph on the Gemini South telescope in Chile to measure these elements in the planet's atmosphere. This is the first time both were measured together on an exoplanet, validating the long-held theory that stars and their planets share similar rock-forming element proportions. The finding strengthens methods for predicting rocky exoplanet compositions and assessing habitability, since stellar chemistry can indicate available building materials. Researchers note such high-resolution measurements are currently only possible with ground-based telescopes, opening new avenues for studying exoplanet atmospheres and potential life-supporting conditions.