Free Astronomy Magazine September-October 2023

34 SEPTEMBER-OCTOBER 2023 ASTRO PUBLISHING South telescope in Chile, part of the International Gemini Observatory operated by NSF’s NOIRLab, and other telescopes, have uncovered evidence of a demolition-derby-like collision of stars or stellar remnants in the chaotic and densely packed region near an ancient galaxy’s su- permassive black hole. “These new results show that stars can meet their demise in some of the densest regions of the Universe where they can be driven to col- lide,” said Andrew Levan, an as- tronomer with Radboud University in The Netherlands and lead author of a paper appearing in the journal Nature Astronomy. “This is exciting for understanding how stars die and for answering other questions, such as what unexpected sources might create gravitational waves that we could detect on Earth.” Ancient galaxies are long past their star-forming prime and would have few, if any, remaining giant stars, the principal source of long GRBs. Their cores, however, are teeming with stars and a menagerie of ultra- dense stellar remnants, such as white dwarf stars, neutron stars, and black holes. Astronomers have long suspected that in the turbulent bee- hive of activity surrounding a super- massive black hole, it would only be a matter of time until two stellar ob- jects collide to produce a GRB. Evi- dence for that type of merger, how- ever, has been elusive. The first hints that such an event had occurred were seen on 19 Octo- ber 2019 when NASA’s Neil Gehrels Never-before-seen way to annihilate a star by NOIRLab − Charles Blue M ost stars in the Universe die in predictable ways, de- pending on their mass. Rel- atively low-mass stars like our Sun slough off their outer layers in old age and eventually fade to become white dwarf stars. More massive stars burn brighter and die sooner in cataclysmic supernova explosions, creating ultradense objects like neu- tron stars and black holes. If two such stellar remnants form a binary system, they also can eventually col- lide. New research, however, points to a long-hypothesized, but never- before-seen, fourth option. While searching for the origins of a long-duration gamma-ray burst (GRB), astronomers using the Gemini