The interstellar comet 3I/ATLAS was detected on July 1, 2025 by the ATLAS telescope in Chile. The object has a chemical composition with high levels of dioxide, exceeding water in a ratio of eight to one. NASA has imposed restrictions on the release of detailed data since October, citing budget constraints due to government shutdowns in the United States.
Astronomers from several countries collect information through independent observatories. The hyperbolic trajectory confirms origin outside the Solar System. The comet activated 6.4 astronomical units from the Sun in May 2025.
- Closest approach to Mars occurred on October 3.
- Orbital probes captured images, but analysis remains pending.
- Perihelion is scheduled for October 30.
Unusual chemical composition
Spectroscopic analyzes show predominance of carbon monoxide. Volatile compounds indicate exposure to cosmic radiation over billions of years.
The core varies between 300 meters and 5.6 kilometers in diameter. The active surface reaches more than 8% of the total.
The absence of heavy metals suggests connection with ancient stars. The estimated age is between 7.6 and 14 billion years.
Agency monitoring
Collaboration with the European Space Agency fills data gaps. The Mars Express and ExoMars Trace Gas Orbiter probes recorded infrared images.
Observatories in Chile and Europe have been monitoring the object since May. The James Webb Telescope confirmed ultraviolet emissions in August.
The Hubble Telescope plans observations in November for spectroscopy. The trajectory passes 1.4 astronomical units from the Sun.
Trajectory and speed
The speed varies from 210 to 221 thousand kilometers per hour. Increases occur during solar approach.
The estimated mass is 1,000 to 10,000 times greater than that of typical comets. There are no signs of fragmentation so far.
The minimum distance to Earth will be 240 million kilometers. Unusual negative polarization sparks classification debates.
Earth observations
The ATLAS telescope in Río Hurtado confirmed hyperbolic orbit. The activity began in May with constant brightness until September.
The Vera C. Rubin Observatory captured images in June. The Exoplanet Transit Satellite recorded data prior to the discovery.
Emission records
Symmetrical patterns of gas traces appear in captures. Vibrations in the core indicate complex internal structure.
Metallic grains are present on the surface. Accelerations near planets surprise gravitational models.
International collaborations
The proposals include integration of data from multiple missions. Observatories in the Southern Hemisphere prioritize night sessions.
Bayesian analyzes calculate origin probabilities. High resolution images are expected after perihelion.
These joint efforts extend the observation window before the comet leaves the Solar System, projected for December 2025, when ground-based telescopes will still be able to record it on receding trajectories.
