Interstellar comet 3I/Atlas is defined as a primitive carbonaceous body with active cryovolcanic activity

Researchers published a study that classifies comet 3I/Atlas as a primitive carbonaceous object rich in metals and water ice. The body, the third interstellar visitor confirmed at Sistema Solar, shows intense cryovolcanic activity during its approach to Sol. The discovery occurred in July 2025 and the conclusions come from detailed spectral analysis.

The object maintains its original composition preserved for billions of years in interstellar space. Imagens released by Administração Espacial Nacional and China show the comet in activity. The research remains in the pre-publication phase, without peer review.

• Estimated diameter varies from 300 meters to 5.6 kilometers
• Rotation period reaches about 16 hours
• Age calculated between 3 and 11 billion years
• Absence of insulating dust blanket confirms pristine state

Identified chemical composition

Analysis compared the spectrum of light reflected by 3I/Atlas with CR carbonaceous chondrite meteorites collected at Antártida. The results indicate high similarity with primitive materials rich in iron and nickel.

The core contains large amounts of water ice and carbonaceous compounds. The structure remains unchanged since its original formation.

Observed cryovolcanic activity

The comet recorded a rapid increase in brightness of 2 magnitudes when it was 2.53 astronomical units from Sol. The phenomenon results from the sublimation of ice that turns directly into vapor.

Pressurized volatile materials are expelled from the interior. The process releases metal-rich dust and ice into space.

This behavior occurs for the first time in millions of years of trajectory. Solar heat activates internal chemical reactions never before exposed.

Rare elements in coma

The diffuse cloud around the core has high levels of CO2 and CO. Também records unusual presence of gaseous nickel.

Leia Tambem

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These components arise from reactions between heated water and metallic grains. The mechanism follows processes similar to the Fischer-Tropsch reactions.

Such reactions generate complex organic compounds inside the object.

Comparison with known objects

The pattern of activity resembles features observed in Plutão and trans-Neptunian objects. Esses distant bodies exhibit cryovolcanism in cold environments.

The absence of prior heating preserved the original chemistry of 3I/Atlas. The visitor offers data on the formation of materials in distant planetary systems.

Implications of Current Research

The study reinforces understanding about interstellar objects that cross Sistema Solar. The pristine composition allows analysis of materials formed outside of solar influence.

New observations continue to follow the comet’s trajectory. Dados collected contribute to models of chemical evolution in deep space.

3I/Atlas remains in a hyperbolic orbit and will leave Sistema Solar in the coming years.