A surprising new picture of interstellar comet 3I/ATLAS (C/2025 N1 ATLAS) reveals the cosmic customer’s ion tail has grown dramatically longer and extra structured — an indication of intensifying exercise because it continues its journey by way of the internal photo voltaic system.
The picture, captured by the Virtual Telescope Project at 11:31 p.m. EDT on Nov. 10 (0431 GMT on Nov. 11), consists of 18 separate 120-second exposures, remotely taken by robotic telescopes situated in Manciano, Italy. Despite the comet being simply 14 levels above the japanese horizon and a shiny 61% moon shining about 70 levels away, a sharply outlined, luminous ion tail is seen.
An ion tail kinds when the solar’s ultraviolet radiation strips electrons from fuel molecules launched by the comet, turning them into charged ions. These ions are then swept away by the photo voltaic wind — a continuing stream of charged particles flowing outward from the solar — creating a protracted, typically bluish tail that at all times factors instantly away from the solar whatever the comet’s course of journey. This tail differs from the mud tail, which tends to look yellowish-white and curves gently alongside the comet’s orbital path.
In the brand new picture, the comet’s shiny core is surrounded by a compact coma and a sharply outlined ion tail stretching roughly 0.7 levels throughout the sky. A faint anti-tail — a function attributable to the observer’s perspective as mud trails alongside the comet’s orbit — can be seen extending in the wrong way. The picture reveals a transparent enhance in exercise in comparison with earlier observations, suggesting that 3I/ATLAS is venting fuel and dirt extra vigorously because it reacts to photo voltaic heating.
3I/ATLAS is simply the third confirmed interstellar object ever detected, following 1I/’Oumuamua in 2017 and 2I/Borisov in 2019. Unlike its predecessors, this customer from one other star system is shiny sufficient to be studied intimately by ground-based telescopes, providing astronomers a uncommon alternative to look at how an interstellar comet behaves beneath the affect of our solar.
The rising size and brightness of the tail recommend growing sublimation of unstable supplies — probably together with carbon dioxide and dirt — which are then swept into house by the photo voltaic wind. Early information recommend that 3I/ATLAS might include a excessive fraction of carbon dioxide ice, providing potential clues to the circumstances within the distant planetary system the place it fashioned, in addition to helpful perception on how comets evolve past our photo voltaic neighborhood.
The Virtual Telescope Project will proceed to watch 3I/ATLAS because it travels by way of the internal photo voltaic system. You can try past images of the comet taken because it was first detected in July of this 12 months.