Interstellar comet 3I/ATLAS reaches perihelion at 204 million km from the Sun this Wednesday

The comet 3I/ATLAS, the third confirmed interstellar object, reaches perihelion on October 29. The closest point to the Sun occurs at 1.36 astronomical units, equivalent to 204 million kilometers. Discovered in July 2025, the celestial body originates from outside the Solar System.

Astronomers monitor the event at 8:47 AM Brasilia time. The distance prevents total fragmentation of the nucleus. Solar heat activates ice sublimation, forming coma and tail.

• Perihelion scheduled for October 29;
• Distance of 204 million km from the Sun;
• Exact time: 8:47 AM in Brasilia.

Discovery and origin

The comet 3I/ATLAS was identified in images from the CCOR-1 coronagraph on the GOES-19 satellite. An amateur astronomer processed daily data behind the Sun.

The origin traces back to an unknown star in the Milky Way. The chemical composition provides data on planetary formation in distant systems.

Perihelion effects

Maximum heat transforms ice into gas in the nucleus. Released dust creates structures visible from Earth.

The distance greater than Mercury’s orbit reduces risks. Minimal fissures may occur in fragile areas.

Brightness increases during the passage. Intense activity highlights chemical elements.

Future trajectory

After perihelion, the comet begins moving away from the Sun. Visibility returns on November 3 in the morning sky.

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The object appears in the Virgo Constellation until November 17. Position rises 3 degrees each day.

Close approaches

Earth receives passage on December 19 at 269 million kilometers. Jupiter influences orbit in March 2026 at 54 million km.

The planet’s gravity slightly alters the trajectory. Brightness decreases until the end of March 2026.

Practical observation

Telescopes capture the comet before dawn. Position 9 degrees above the eastern horizon.

Animations simulate movement through the Solar System. JPL data updates orbital parameters.

The nucleus remains intact after perihelion. Studies confirm structural stability. Composition includes rare metals. Observatories in Namibia record ice jets. Consolidated platforms provide accurate predictions.

Orbital data

Parameters indicate hyperbolic orbit. Speed exceeds solar escape.

• Astronomical unit: 149.6 million km;
• Perihelion: 1.36 AU;
• Earth approach: 1.80 AU;
• Jupiter influence: 0.36 AU.