Astronomers reported on Thursday that сomet 3I/ATLAS, which flew past us last year from another star, presumably originated in a cold, isolated corner of the galaxy that had not yet formed into its own Solar System.
Interstellar comet 3I/ATLAS. Source: phys.org
Observation of сomet 3I/ATLAS
Comet 3I/ATLAS is only the third confirmed interstellar visitor and, in all likelihood, the oldest. Scientists estimate that it may be as much as 11 billion years old, which is more than twice the age of the Sun.
Last autumn, a team of scientists led by the University of Michigan used the ALMA Observatory, located in Chile’s Atacama Desert, to study the comet. This wandering but harmless ice ball was discovered last summer, giving NASA and the European Space Agency enough time to point several space telescopes at it as it flew past Mars in October and made its closest approach to Earth in December. By now, it has long since passed Jupiter and is leaving our Solar System forever, remaining visible only to professionals.
Birthplace of comets and conditions for planetary formation in the distant past
During the study, scientists reported that they had detected an exceptionally high concentration of deuterium, or heavy hydrogen, in the comet’s water. This indicates that the comet originated from a place that was much colder—even before the star of our Solar System formed—than our own cosmic environment, said Teresa Paneque-Carreno of the University of Michigan.
She noted that, although our Sun was likely surrounded by other newborn stars during its formation, the star around which this comet orbits may have been more isolated, resulting in less heating and colder conditions.
The comet’s exact origin remains unknown. According to observations by the Hubble Space Telescope, its nucleus measures between a quarter of a mile and 3.5 miles (440 meters to 5.6 kilometers). It is traveling at a speed of 137,000 miles per hour (220,000 km/h).
“Linking all these “puzzle pieces together may give an idea to how the planet-forming conditions were at these early times,” noted Paneke-Carreno.
The first known interstellar object to wander into our solar system—Oumuamua—was discovered by a telescope in Hawaii in 2017. In 2019, comet 2I/Borisov appeared, named after the Crimean amateur astronomer who first spotted it.
According to phys.org