Do interstellar comets differ in composition from Solar System comets? · revision history

Revision 2

Accepted · cosmetic change · record

Changes against revision 1:

Title
Do interstellar comets differ in composition from Solar System comets?
Plain
2I/Borisov carried an unusually large share of carbon monoxide and 3I/ATLAS showed a coma dominated by carbon dioxide. Whether such differences reflect where they formed or billions of years of cosmic-ray exposure in space is unknown.
Precise
Compare volatile and metal abundance ratios ($\mathrm{CO}/\mathrm{H2O}, \mathrm{CO2}/\mathrm{H2O}, \mathrm{Ni}/\mathrm{Fe}$) of 2I/Borisov and 3I/ATLAS with Solar System comets, and determine whether the differences reflect formation location and stellar environment or processing during Gyr-long interstellar travel. The answer is a classification of composition differences by origin, with predictions testable on future objects.
Settled by
Spectroscopic surveys of a sample of interstellar comets compared with laboratory and model predictions of cosmic-ray processing of ices.
Kind
well-posed
Answer type
classification
References
(empty)
Literature status
open
Status note · changed
Revision 1: JWST spectra in 2025 showed a CO2-dominated coma of 3I/ATLAS ($\mathrm{CO2}/\mathrm{H2O} \sim 8$), VLT spectra detected nickel vapor with little or no iron, and its non-gravitational acceleration near perihelion is attributed to outgassing.
Revision 2: JWST spectra in 2025 showed a $\mathrm{CO_2}$-dominated coma of 3I/ATLAS ($\mathrm{CO2}/\mathrm{H2O} \sim 8$), VLT spectra detected nickel vapor with little or no iron, and its non-gravitational acceleration near perihelion is attributed to outgassing.
Posed since
(empty)

Decisions