Overview

• An MDM Observatory 10‑night campaign reports the onset of optical gas activity with a weak CN line and an upper limit on C2 placing 3I/ATLAS among the most carbon‑chain–depleted comets observed.
• JWST and NASA’s SPHEREx find a CO2‑dominated coma, with estimated release rates far exceeding water and carbon monoxide, pointing to CO2 as the primary driver of activity at current distances.
• Archival TESS imagery identifies the object on May 7, 2024, extending the observational arc and improving constraints on its path through the solar system.
• A new arXiv preprint by Davenport and colleagues urges routine technosignature checks for interstellar objects; 3I/ATLAS has already been scrutinized by facilities including the Allen Telescope Array, Hubble and Webb with no artificial signals reported.
• High‑profile claims about unusual morphology, composition and a hypothetical Mars‑bound precursor probe remain unconfirmed, as major agencies continue to classify 3I/ATLAS as a comet under active study.