Interstellar comet 3I/Atlas has an expanded tail recorded by Italian observatory in new images

The interstellar comet 3I/Atlas, a cosmic traveler originating outside our Sistema Solar, has become the focus of astronomers after showing a remarkable expansion in its tail. The phenomenon was documented in detail on November 11, 2025 by a robotic unit from Projeto Telescópio Virtual, operated from Observatório Astronômico Bellatrix, in Manciano, in Itália. The images were captured shortly after the comet reached perihelion, its closest approach to Sol, revealing much more intense activity than predicted by some scientific models.

This celestial object is the third of its kind to be identified by scientists, following the discoveries of Oumuamua in 2017 and Borisov in 2019. of years. Nasa has already confirmed that, despite its unusual trajectory, the comet does not pose any risk of collision with Terra, passing at a safe distance from our planet.

The recent observation is particularly significant because the comet survived its close passage to Sol without fragmenting, a common fate for celestial bodies under intense radiation and gravitational pull. The survival and increased activity, evidenced by the sharper and more stretched ion tail, provides valuable data to the scientific community about the composition and resilience of objects formed in other stellar systems.

Technology behind the capture

The image that revealed the enlarged tail of the 3I/Atlas was obtained by the ARTEC250+Paramount ME+C3Pro61000EC robotic unit. Este high-precision, remotely operated equipment was key to overcoming the observational challenges posed by the comet’s perspective during and after perihelion, when Sol’s brightness can outshine less luminous objects.

Projeto Telescópio Virtual, led by astrophysicist Gianluca Masi, is an initiative that uses a network of robotic telescopes to make astronomical observations accessible to the global public. Através from its platform, the project not only contributes scientific data, but also democratizes access to astronomy, carrying out live broadcasts of important celestial events.

Unique features of the comet

In-depth studies on 3I/Atlas revealed a distinct chemical composition. Análises carried out with Telescópio Espacial James Webb indicated that its coma, the cloud of gas and dust surrounding the nucleus, is exceptionally rich in carbon dioxide (CO₂), presenting a very high proportion in relation to water, something unusual for comets from our Sistema Solar.

Its interstellar origin is confirmed by its hyperbolic orbit, an open trajectory that indicates that the object is not gravitationally bound to Sol and will continue its journey back to deep space. Atualmente, the comet is moving at an impressive speed of approximately 210 thousand kilometers per hour, a pace that will take it far from our system in the coming years.

The ionic tail, which has become more prominent, is formed by gases that are ionized by ultraviolet radiation from Sol and pushed by the solar wind. Além from it, astronomers also observed an “antitail,” a rare optical phenomenon in which some of the dust appears to point in the direction of Sol, depending on the observer’s perspective on Terra.

Global monitoring and observations

The passage of 3I/Atlas has been accompanied by an international observation campaign. Missões spacecraft in orbit around Marte, such as Tianwen-1 from

On the ground, Rede Internacional of Alerta of Grandes observatories, such as Gemini Sul, located at Chile, also recorded the growth of the tail, corroborating the data on the growing activity of its core.

The diameter of the comet’s nucleus is still the subject of study, with estimates of Nasa varying between 320 meters and 5.6 kilometers. Dados obtained by Telescópio Espacial Hubble suggests that the rate of dust loss from 3I/Atlas is similar to that of long-period comets originating from Nuvem of Oort, the most distant region from our Sistema Solar, which adds another layer of complexity to its study.

The significance for astronomical science

The passage of 3I/Atlas through our Sistema Solar represents a rare and invaluable scientific opportunity. Como a direct sample of another star system, its chemical composition offers a window into planet formation processes occurring elsewhere in the galaxy. The high concentration of carbon dioxide, for example, may indicate that it formed in a region very different from that where the comets in our system originated. The analysis of its structure, which resisted the solar approach, provides clues about the cohesion and internal composition of interstellar celestial bodies, challenging and improving existing theoretical models. Cada data collected about its orbit, speed, rotation and composition helps scientists piece together the puzzle of the formation and evolution of planetary systems, including our own. The comparison between 3I/Atlas and “native” comets allows us to better understand the diversity of cosmic environments and the conditions necessary for the emergence of planets and, potentially, life.

Next steps and how to follow up

For interested audiences, Projeto Telescópio Virtual has scheduled a live broadcast of the comet’s passage for November 19th, starting at 1:15 am (Brasília time), which will be made available on its YouTube channel. Astrônomos amateurs equipped with modest telescopes can also try to observe 3I/Atlas, it is recommended to look for places with low light pollution and observe the sky in the northeast direction just before dawn.