Breakthrough Tracker record
Water D/H in 3I/ATLAS as a probe of formation conditions in another planetary system
ALMA constrained the water deuterium-to-hydrogen ratio in interstellar comet 3I/ATLAS to more than 6.6 × 10^-3. That lower bound is over 40 times Earth's ocean value and over 30 times typical Solar System comet values.
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- Stable ID
3i-atlas-water-deuterium-2026- Revision
3i-atlas-water-deuterium-2026.v1- Field
- Astronomy · Astrochemistry, comets and planetary-system formation
- Evidence
- Tier 1 · Peer reviewed: Yes
- Record state
- Current · Peer-reviewed observational result
- Last checked
AI role
No AI assistance was disclosed in the paper or linked reporting.
Record details
- Problem or result
- Measuring an isotopic formation tracer in material from outside the Solar System
- Authors
- Luis E. Salazar Manzano, Teresa Paneque-Carreño, Martin A. Cordiner and collaborators
- Institutions
- University of Michigan, NASA Goddard, JPL/Caltech, UC Berkeley, Observatoire de Paris/CNRS, NRAO and partners
- Result date
- April 23, 2026
Why it matters
The result provides a direct chemical constraint on planetary material formed around another star and points to unusually cold or weakly processed formation conditions.
Limits
The result is a lower bound derived from HDO detection and H2O non-detection, not a precise ratio. The birth-environment inference depends on chemical and excitation modelling and does not identify the comet's home star.
Sources
- Primary: Primary paper in Nature Astronomy
- Independent: Le Monde specialist reporting
Correction and revision history
- Initial entry.
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