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First Post-Perihelion Images Capture 3I/ATLAS After Sun Passage

Unusual brightening plus measured non‑gravitational motion have triggered a global observing push ahead of its safe December 19 flyby.

Overview

  • Lowell Observatory’s Qicheng Zhang released what appear to be the first optical images after perihelion on October 31, then confirmed the object is detectable with small amateur telescopes at dawn.
  • Solar-monitoring spacecraft (SOHO, STEREO‑A, GOES‑19) recorded an unprecedented rapid brightening and a distinctly blue, gas‑dominated coma before perihelion, according to analyses by Zhang and Karl Battams.
  • Swift observations reported ultraviolet signatures of OH at unusually large distances from the Sun, implying active water loss estimated at roughly tens of kilograms per second.
  • JPL/NASA tracking indicates measurable non‑gravitational acceleration, yet officials reiterate there is no threat to Earth with the closest approach set for December 19 at about 1.8 AU (~270 million km).
  • While a minority has floated artificial‑origin hypotheses, most astronomers describe 3I/ATLAS as an active comet, and international teams are coordinating November–December observations to test competing explanations.