Using the Atacama Large Millimeter/submillimeter Array (ALMA), scientists have discovered that the invading interstellar comet 3I/ATLAS formed in a much colder region of the Milky Way than our solar system.
The discovery came when scientists made the first measurement of so-called semi-heavy water (or deuterated water) from an object that originated beyond the solar system. Deuterated water refers to water in which a hydrogen atom is replaced with deuterium, a heavy hydrogen isotope that has an atomic nucleus composed of a proton and a neutron. ALMA measurements of deuterated water revealed that 3I/ATLAS It contains about 30 times more semi-heavy water than that found in kites that originate in the solar system.
“Our new observations show that the conditions that led to the formation of our solar system are very different from how planetary systems evolved in different parts of our galaxy,” said team leader Luis E. Salazar Manzano of the University of Michigan. said in a statement.
Manzano and his colleagues studied 3I/ATLAS when it reached its closest point to the sun, a feat made possible by the ability of ALMA’s 66 radio antennas to point toward the sunsomething optical telescopes cannot do due to the glare of sunlight.
An interstellar snowball
The high water content of comets in the solar system means they are often called “dirty snowballs.” This water contains a record of the chemistry of the environment in which comets formed at the time of their birth, which for comets in our solar system was approximately 4.6 billion years agowhen planets were also forming around the rising sun.
Comets not only contain ordinary water composed of two hydrogen atoms with nuclei composed of only one. proton attached to an oxygen atom; They also contain deuterated water molecules. In the comets of the solar system there is one molecule of deuterated water for every 10,000 molecules of ordinary water, but in 3I/ATLAS the proportion between semi-heavy water and water is 30 times greater. This proportion is, in turn, 40 times greater than the same proportion in the Earth’s oceans.
This high ratio indicates that 3I/ATLAS formed in an exceptionally cold and chemically distinct environment somewhere else on the planet. Milky Way.
“The chemical processes that lead to the improvement of deuterated water are really temperature sensitive and generally require environments colder than about 30 Kelvin, or about -406 degrees Fahrenheit. [207 degrees Celsius]”Manzano said.
The ratio acts as a record of the chemical environment of 3I/ATLAS Home Systemhaving remained intact throughout the interstellar invader’s long journey to the solar system. The ratio is also important because the abundances of deuterium and hydrogen throughout the universe are thought to have been established during the big explosion itself.
“Each interstellar comet brings a little of its history, its fossils, from other places,” said Teresa Paneque-Carreño, a team member from the University of Michigan. “We don’t know exactly where, but with instruments like ALMA we can begin to understand the conditions there and compare them to our own.”
The team’s research was published Thursday (April 23) in the journal. Nature astronomy.
