Rare Near-opposition Alignment of 3I/ATLAS on 2026 January 22
Abstract
Abstract We point out that on 2026 January 22, the interstellar object 3I/ATLAS will align to within an exceptionally small angle, α = 0 . ° 69 , with the Earth–Sun axis. This rare alignment provides unique circumstances for measuring the opposition surge and polarimetric properties of interstellar cometary dust. We characterize the alignment geometry, outline key scientific opportunities, and define the observational requirements for data collection. Observations before and after the alignment time offer an unprecedented opportunity which may not repeat for decades, for characterizing the albedo, structure, and composition of interstellar matter.
Fields of Study & Subjects
Astrophysics and Star Formation Studies
Astro and Planetary Science
Stellar
planetary
and galactic studies
Publication details
- Journal / source
- Research Notes of the AAS
- Publisher
- American Astronomical Society
- Volume
- 10
- Issue
- 1
- Pages
- 17–17
- Publication date
- 22 January 2026