Free Astronomy Magazine May-June 2026

MAY-JUNE 2026 G emini South, one half of the International Gemini Observatory, a Program of NSF NOIRLab, is seen here with its laser guide star in action. Both of the Gemini telescopes use laser guide stars to provide data for the calibration of their adaptive optics, systems of deformable mirrors that compensate for fluctuations in the upper atmosphere which can blur the images of distant stars and galaxies. The laser excites trace gas particles high in Earth’s upper atmosphere. Software then analyzes feedback from the laser to provide a model for the adaptive optics to map against. The laser guide stars can also be augmented by additional adap- tive optics systems that use images of real stars from the telescope itself, such as the Natural Guide Star Next Generation Sensor. [International Gemini Observa- tory/NOIRLab/NSF/AURA/T. Slovinský] cutting-edge instrument, the Gem- ini High-resolution Optical SpecTro- graph (GHOST). In March 2025, GHOST observed the occultation for just over two hours, dispersing the light from the star into a spectrum serving a star being occulted by a disk surrounding a secondary object is exceptionally rare, with only a handful of known examples. To investigate the cloud’s composi- tion, the team used Gemini South’s tionally bound to a secondary object that itself orbits the star in the outer reaches of its planetary system. While the nature of this object re- mains unknown, it must be massive enough to hold the cloud together. Observations constrain it to be at least a few times the mass of Jupiter, though it could be larger. Possibili- ties range from a planet to a brown dwarf to an extremely low-mass star. If the mystery object is a star, the cloud would be classified as a cir- cumsecondary disk — a debris disk orbiting the less massive member of a binary system. If the object is a planet, it would be a circumplane- tary disk. In either case, directly ob-