Overview
- JAXA’s XRISM observed 3I/ATLAS Nov. 26–28 with 17 hours of exposure, revealing a faint X-ray halo extending roughly 5 arcminutes, or about 400,000 kilometers.
- The signal likely arises from charge-exchange interactions between solar-wind ions and neutral gases in the coma, with features associated with carbon, nitrogen and oxygen distinct from background emission.
- NASA released new Hubble images from Nov. 30 that track the comet as a bright moving point against star streaks, with further observations planned.
- ESA’s Juice spacecraft imaged the coma in early November and indicated the possibility of two tails, complementing a broader campaign spanning Mars orbiters, Lucy, SOHO, PUNCH, MAVEN and Perseverance.
- NASA’s SPHEREx measurements found abundant water ice and carbon dioxide in the coma, and orbital tracking places closest approach to Earth on Dec. 19 at roughly 170 million miles.