Astronomers studying the interstellar comet 3I/ATLAS confirmed that the object solidified its nucleus under temperatures below 30 Kelvin in the remote outskirts of another star system, according to findings published in the Monthly Notices of the Royal Astronomical Society. The body marks only the third macroscopic celestial object originating outside the Solar System ever recorded and inspected directly by modern astrophysics. Optical and spectroscopic instruments captured signatures of pristine frozen gases that have remained unaltered since the comet condensed during the birth of its home planetary system.
This extreme cold shielded the internal matter of the rocky-icy block from any major thermal metamorphism throughout cosmic history. Because of such prolonged isolation, primitive volatile compounds survived across eons without experiencing substantial chemical alteration or structural decay.
Spectroscopic measurements expose chemical composition preserved in deep freeze
Spectroscopic data extracted from the coma surrounding 3I/ATLAS reveal massive concentrations of carbon monoxide alongside volatile substances that freeze solid strictly below 30 Kelvin, a boundary typical of the coldest exterior zones in distant protoplanetary disks. Demonstrating this rare molecular makeup in the Monthly Notices of the Royal Astronomical Society, researchers determined that the body grew far away from its primary star’s warmth throughout the gravitational accretion of cosmic dust, well before violent gravitational interactions ejected it into interstellar space for a multi-million-year journey. The nucleus never encountered enough stellar radiation to disrupt its inner volatile matrix prior to its recent visit. Severe cold locked every primordial element in place.
Check out: Interstellar comet 3I/ATLAS formed below -240 °C around an ancient star with low metal levels
Researchers tracked the relative abundances of simple volatile gases to reconstruct the initial coordinates of that remote stellar nursery. Ground-based instruments documented a steady rise in outgassing rates as the object approached the Sun and solar radiation began heating its frozen surface.
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The rapid loss of carbon monoxide unfolded at significantly higher rates than the conventional sublimation observed in typical water-ice comets. This aggressive evaporation created an extensive gaseous shroud around the nucleus long before it reached perihelion. Observing teams on Earth leveraged high-resolution spectrometers to dissect these light emissions into specific spectral lines, confirming the extraordinary preservation of an alien celestial body.