Interstellar comet 3I/ATLAS surprises with structure of up to five tails in recent images
The interstellar comet 3I/ATLAS, the third object confirmed to come from outside the Solar System, exhibited a complex structure of tails in observations carried out in November 2025. Captures made by amateur and professional astronomers showed between four and five tails or jets of dust and gas spreading in varying directions. The phenomenon occurred as the comet approached perihelion, the closest point to the Sun, intensifying its activity.
Discovered in July 2025 by the ATLAS system, 3I/ATLAS travels on a hyperbolic trajectory at around 60 km/s. Initially classified as a possible asteroid, the object revealed a coma and tails typical of comets as it approached the Sun.
- The core measures between 300 meters and 5.6 km in diameter.
- The composition includes ice rich in carbon dioxide.
- Sublimation generates jets that form the observed structures.
These characteristics confirm its natural cometary nature.
Observations that revealed multiple tails
Images captured on November 8, 2025 in Austria, by Michael Jäger and other astronomers, showed the complex structure of thecomet. The tails appeared as fan-like extensions, the result of jets of material ejected from the nucleus.
Other captures, made on November 9, recorded two distinct tails. One of them, made of dust, extended for about 30 arc minutes, equivalent to the apparent diameter of the Full Moon.
These records highlight the intense activity of 3I/ATLAS at still considerable distances from the Sun.
Formation of comet tails and jets
Solar heat causes sublimation of ice in the comet’s nucleus. Gas and dust escape through cracks, forming jets that push material in specific directions.
Solar radiation pressure and solar wind shape the tails. In some cases, observational geometry creates anti-tails or multiple apparent structures.
In 3I/ATLAS, the combination of active jets and side view generated the appearance of four to five separate extensions.
Comparison with previous interstellar comets
The first interstellar object, 1I/’Oumuamua, detected in 2017, had no visible tails. The 2I/Borisov, from 2019, displayed a classic coma and single tail.
3I/ATLAS differs in its early activity and more complex structures. Observations indicate a high proportion of CO2 in relation to water, common in distant objects.
These differences provide data on comet formation in other stellar systems.
3I/ATLAS activity after perihelion
The comet reached perihelion in October 2025, about 1.4 astronomical units from the Sun. After passage, images showed well-defined ionic and dust tails.
There was no total fragmentation recorded until November. The observed non-gravitational acceleration is explained by asymmetric ejection of material.
Telescopes like Hubble and ground-based observatories continue to monitor the object as it moves away.
Origin and trajectory of the interstellar visitor
3I/ATLAS probably formed billions of years ago around another star. Prolonged exposure to cosmic rays created altered outer crust on its surface.
Its hyperbolic orbit confirms a unique passage through the Solar System. High speed prevents gravitational capture by the Sun.
The comet now heads towards interstellar space, without the risk of collision with planets.
Amateur and professional observations in November
Astronomers in Europe and other continents recorded the multiple tails using medium-sized telescopes. Image processing highlighted thin jets and main dust tail.
- Ionic tail appears straight and bluish in some captures.
- Dust tail bends due to radiation pressure.
- Additional jets create fan appearance in long exposures.
- Current magnitude allows observation with accessible equipment.
These records enrich the database on the comet.
3I/ATLAS remains active in November 2025, with tails visible in detailed images. Studies based on these observations help to understand objects from other stellar systems. Telescopes keep track as the comet gradually moves away from the Sun and Earth.
