A new image captured by an astrophotographer at Porto Rico reveals details of the continued activity of the interstellar comet 3I/ATLAS, almost three weeks after its passage through perihelion on October 29, 2025. The recording, taken on November 17 at Aguadilla, shows the object with an active coma and elongated tail, driven by solar heating that releases gas and dust. Astrônomos highlight that this observation, published in SpaceWeather Gallery, confirms the comet’s persistence despite the expected loss of brightness.
Comet 3I/ATLAS, the third interstellar visitor detected in Sistema Solar, follows a hyperbolic trajectory at 221 thousand km/h, originating from another star system billions of years ago. Especialistas from NASA and ESA monitor the phenomenon to understand its unique composition, different from local comets.
- The thin tail is guided by the solar wind, with particles ejected at high speed.
- The asymmetric coma indicates surprising emission of post-perihelion material.
- Global observations provide data for models of interstellar dynamics.
Capture details at Porto Rico
Efrain Morales, an astrophotographer based at Aguadilla, obtained the image on the night of November 17th with equipment dedicated to celestial observations. The record highlights the thin and defined tail, the result of interaction with the solar wind that pushes ionized particles away from the nucleus.
This photo appears at a key moment, when the comet moves away from Sol, 190 million miles from Terra, allowing morning visibility in constellations like Virgem.
Structures observed in the coma
The asymmetric coma revealed in the image signals accelerated loss of material, with gas and dust released at rates higher than those of comets like 2I/Borisov in 2019. Astrônomos note that the nucleus maintains a stable brightness, contrasting with the rapid weakening typical of interstellar objects.
Preliminary data indicate a diameter between 5 and 11 km, with a composition rich in carbon dioxide and water, analyzed by telescopes such as Hubble and James Webb.
Contributions from international observatories
Projeto Telescópio Virtual, in Itália, recorded 3I/ATLAS on November 11, exhibiting a narrow ionic tail from ultraviolet interaction with released gas. Essa structure is formed when solar radiation ionizes particles, facilitating push by the solar wind.
Observatories on Chile, such as Gemini Sul, captured images on November 3, revealing an expansive coma more than 56,000 km long.
Agência Espacial Europeia plans to use the JUICE mission for data between November 2 and 25, while China’s Tianwen-1 telescope acquired sequences in October at 30 million km.
Evolution of post-perihelion activity
After perihelion on October 29, the comet maintained emission of jets of dust and gas, visible in photos on November 11 by Telescópio Gêmeo of Dois Metros in Espanha. The tail has grown three million km, a sign of evolving geometry that makes the object more visible in the morning sky.
Records from the Mars Reconnaissance Orbiter probe on October 2 show a halo of gas and dust, or coma, around the nucleus during its passage by Marte.
NASA revelations on live broadcast
NASA held an event on November 19 at Centro Goddard, at Maryland, to present never-before-seen images collected by missions such as PUNCH, Lucy and MAVEN. The photos, captured between September and October, show the comet 231-235 million miles from Terra, with Mars passing nearby in a combined view.
Instruments on Lucy recorded the object on September 16, stacking images to highlight short elongation of the tail on the right.
Implications for interstellar studies
3I/ATLAS offers insights into formation in ancient star systems, predating Sistema Solar by up to 8 billion years. Observações confirm the absence of technological signatures, reinforcing the classification as a natural comet.
The closest approach to Terra occurs on December 19th at 269 million km, without risk of collision.
- Ground-based telescopes track post-perihelion magnitude 7-8 brightness.
- Space missions provide three-dimensional views of the coma and tail.
- Data supports IAWN warning exercises through January 2026.