Post #5754

New Research Reveals That Interstellar Comet 3I/ATLAS Formed in a System Far Colder Than Our Own 3I/ATLAS created quite the buzz as it flew through our Solar System. As just the third interstellar object (ISO) ever detected, what our instruments observed as it approached our Sun and began heading back to deep space provided tantalizing clues about the star system in which it formed. In particular, new observations from the Atacama Large Millimeter/submillimeter Array (ALMA) have yielded the first-ever measurement of deuterated water (or "semi-heavy water") in an ISO. The discovery provides a chemical window into the cold conditions that characterize its home star system. The research was led by PhD student Luis E. Salazar Manzano, a PhD student at the University of Michigan, and assistant professor Teresa Paneque-Carreño, the Principal Investigator of the ALMA Director's Discretionary Time program that made the discovery. They were joined by researchers from the National Radio Astronomy Observatory (NRAO), the Laboratory for Instrumentation and Research in Astrophysics (LIRA), the Leach Science Center, the Millennium Nucleus on Young Exoplanets and their Moons (YEMS), and NASA's Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL). The team's observations were made in December 2025, six days after 3I/ATLAS reached its closest point to the Sun. This narrow observation window was made possible by two things. First, there's the ALMA's Atacama Compact Array (ACA), a series of four 12-meter (39.4 ft) and 7-meter (23 ft) telescopes grouped in a compact configuration to combine measurements (aka short-baseline interferometry), allowing them to see very faint objects in space. Second, there's ALMA's unique ability to point toward the Sun, which most optical telescopes cannot. As Paneque-Carreño noted in an NRAO press release Most instruments can't point toward the Sun, but radio telescopes like ALMA can. We were able to observe the comet within days after perihelion, just as it peeked out from its transit behind the Sun. This gave us a constraint on these molecules that's not possible using other instruments. Source:Universe Today @EverythingScience