Particle.news
Download on the App Store

Interstellar Comet 3I/ATLAS Reappears With Green Glow and a Puzzling ‘Missing’ Tail

Fresh images from Tianwen‑1 plus ground observatories set up targeted measurements before a safe, distant flyby next month.

Overview

  • Post‑perihelion images taken on November 5 show a bright green‑blue coma, with researchers attributing the color to diatomic carbon emission and CO2‑rich outgassing.
  • The comet’s dust tail is not obvious in new views; Lowell Observatory’s Qicheng Zhang says the tail is foreshortened along our line of sight, while other observers report anti‑tail geometry under active study.
  • Analysts report measurable non‑gravitational acceleration and estimate significant mass loss of roughly 13% after perihelion, which agencies say is consistent with outgassing but requires further investigation.
  • China’s Tianwen‑1 Mars orbiter released close images showing a nucleus and expansive coma, as coordinated campaigns by IAWN, JWST in December, and ESA’s JUICE in November aim to refine size, composition, and dynamics.
  • High‑resolution MRO/HiRISE images exist but remain unreleased during a U.S. government shutdown despite a congressional request, and ESA confirms a safe closest approach on December 19 at about 270 million kilometers.