The interstellar object 3I/ATLAS, discovered in 2025, exhibited behavior outside the standard expected for natural comets between November 22nd and 24th. Imagens captured during this period recorded a bright coma, a long tail and a well-defined antitail directed towards Sol. Astronomer Avi Loeb, from Universidade Harvard, highlighted that the antitail is larger than usual in size and intensity.
The non-gravitational acceleration detected near perihelion also attracted attention. Esse type of movement requires significant mass loss, difficult to be explained by common cometary processes alone.
Features observed in the new images
Photographs taken on November 22, 23 and 24 show the clear formation of a coma around the nucleus. The main tail extends in the opposite direction to Sol, as occurs in active comets.
The antitail, however, appears in the solar direction, a result of the terrestrial perspective aligned with the object’s orbital plane. Sua extension and brightness indicate large volume ejection of material.
Mass loss greater than expected
The intensity of the antitail suggests a very high sublimation rate. Natural Cometas lose mass mainly through ice evaporation when they approach Sol.
In the case of 3I/ATLAS, the volume of material required to generate the observed structure exceeds traditional models. Loeb points out that the amount required would make the object unstable in a short time if it were just natural.
Acceleration not explained by gravity
Measurements revealed additional acceleration beyond the gravitational pull of Sol. Esse effect has already been recorded in other comets, generally attributed to gas jets.
The magnitude recorded in 3I/ATLAS, however, demands a greater amount of ejected material. Alternativas technological technologies would produce the same impulse with less mass, according to the researcher.
Next Observation Steps
Large telescopes should perform new captures in December 2025. Esses equipment will allow greater resolution of the object’s structure.
- Detailed spectral analysis of coma and tail material
- Precise measurement of the chemical composition of the jets
- Continuous trajectory monitoring to confirm acceleration
- Comparison with data from known solar system comets
The results will help define whether the characteristics have a natural origin or require alternative explanations.
Differences from previous objects
1I/’Oumuamua, the first interstellar confirmed in 2017, showed non-gravitational acceleration without a visible coma or tail. 2I/Borisov, the second object, behaved like a typical comet.
The 3I/ATLAS combines developed coma with high acceleration and strong anti-tail. Essa combination had not yet been recorded in objects of extrasolar origin.
Observations remain ongoing to track the comet’s evolution as it moves away from perihelion.