Free Astronomy Magazine July-August 2026

22 ASTRO PUBLISHING JULY-AUGUST 2026 WASP-189 b echoes the composition of its host star by NOIRLab Josie Fenske A lmost 320 light-years away in the Libra constellation lies WASP-189 b, an exoplanet known as an ultra-hot Jupiter (UHJ). UHJs have temperatures high enough to vaporize rock-forming elements like magnesium (Mg), sili- con (Si), and iron (Fe), offering a rare opportunity to see these ele- ments using spectroscopy — the technique of breaking up light into its component wavelengths to iden- tify the presence of chemicals. An international team of as- tronomers led by Jorge Antonio Sanchez, a graduate student at Arizona State University (ASU) ob- served WASP-189 b using the high- resolution Immersion GRating IN- frared Spectrograph (IGRINS) when it was mounted on the Gemini South telescope in Chile. This powerful instrument allowed them to simultaneously measure T his illustration shows an ultra- hot Jupiter orbiting a blue-white A-type star. [International Gemini Observatory/NOIRLab/NSF/AURA/ J. Pollard]