NASA reveals detailed chemical composition of interstellar comet 3I/ATLAS with organic molecules
Nasa released recent analyzes from the SPHEREx space telescope that identify specific substances in the coma of the interstellar comet 3I/ATLAS. The observations, carried out mainly in December 2025 and published in February 2026, detected water, carbon dioxide, carbon monoxide, dust and several organic molecules around the nucleus. Esses compounds arise from the sublimation of ice when the object approaches Sol. The comet registered a significant increase in brightness after perihelion, associated with the intense release of materials preserved for billions of years.
The data reinforces the extraterrestrial origin of 3I/ATLAS, the third confirmed interstellar object. Descoberto on July 1, 2025 by the ATLAS system in Chile, it follows a hyperbolic trajectory and does not belong to Sistema Solar. The information contributes to studies on comet formation in other stellar systems.
- Water in the form of vapor
- carbon dioxide
- Carbon monoxide
- Methanol
- Methane
- hydrogen cyanide
- dust particles
These elements form the extensive coma observed.
Discovery and trajectory of the object
The ATLAS system identified comet 3I/ATLAS in July 2025 during routine scans of the night sky. The high velocity and hyperbolic orbit quickly confirmed its origin outside of Sistema Solar.
Astronomers classified the object as the third known interstellar visitor. Ele follows ‘Oumuamua, detected in 2017, and 2I/Borisov, observed in 2019.
🚨Comet or spaceship? 😱👀 NASA responds after interstellar visitor 3I/ATLAS suddenly brightens ☄️🛸
— 3I/ATLAS updates (@Defence12543)February 8, 2026
⚠️New infrared observations from NASA’s SPHEREx space telescope reveal dramatic changes in interstellar comet 3I/ATLAS as it made its final pass through our solar system 🌌…pic.twitter.com/7SnXYW0773
Initial orbital characteristics
The trajectory of 3I/ATLAS indicated passage through perihelion in October 2025, approximately 1.4 astronomical units from Sol. The object reached relative proximity to Marte and Terra in subsequent months, without risk of collision. Atualmente, it moves away towards interstellar space.
Activation after solar passage
Comet 3I/ATLAS showed intense activity in December 2025, months after perihelion. Solar heat penetrated deep layers of the core, causing late sublimation of ices and release of trapped gases.
This eruption generated a significant increase in the object’s brightness. Observações recorded expansion of the coma and formation of a more defined tail.
The process demonstrates that inner layer materials remain protected for long periods. The release continues even as the comet moves away from Sol.
Observations by the SPHEREx telescope
The SPHEREx space telescope captured infrared data from 3I/ATLAS during its active phase. The mission, designed to map the sky in multiple bands, identified spectral signatures of specific compounds in the coma.
The instruments detected a carbon dioxide coma stretching hundreds of thousands of kilometers. Essa structure reveals abundance of CO2 in the frozen core.
Details of the detected molecules
The analyzes confirmed the presence of organic molecules such as methanol, methane and hydrogen cyanide. Esses compounds arise in common chemical processes in cold space environments.
The combination also includes water vapor and carbon monoxide in varying proportions. Partículas of dust accompany the gases, forming a visible envelope around the nucleus.
Comparison with other interstellar comets
3I/ATLAS differs from ‘Oumuamua, which exhibited little cometary activity. Já 2I/Borisov showed similar coma and tail, with high carbon monoxide concentration.
The presence of organic molecules in 3I/ATLAS aligns with patterns observed in Sistema Solar comets. The specific ratios indicate formation conditions in a distant star system.
Rarity of interstellar visitors
Only three interstellar objects have been confirmed to date. The 3I/ATLAS detection represents a rare opportunity to study primordial materials from another region of Via Láctea.
These comets preserve compounds formed billions of years ago. Eles travel through interstellar space before temporarily entering Sistema Solar.
Old materials released
The compounds detected in 3I/ATLAS remained frozen for periods estimated at more than seven billion years. Passage through Sol exposed these materials to direct observation for the first time.
Researchers highlight that the release includes rich carbon, coming from deep layers. Essa feature provides data on prestellar chemistry in other environments.
Contributions to astronomical studies
SPHEREx observations add information to the database on interstellar objects. The results help to understand cometary formation processes on galactic scales.
The combination of gases and organics reinforces models of element distribution in the universe. Dados spectra serve as a reference for future detections.
Future monitoring perspectives
3I/ATLAS continues to be tracked by ground- and space-based telescopes in 2026. Sua Increasing distance reduces visibility, but infrared observations still pick up residual signals.
In March 2026, the comet will pass close to Júpiter, with minimal change in its hyperbolic trajectory. Ele will continue towards deep space without returning.
Substances identified in coma
- Water vapor from sublimated ice
- Carbon dioxide in extended coma
- Carbon monoxide in high concentrations
- Methanol as the main organic molecule
- Methane detected in traces
- Hydrogen cyanide at measurable levels
- Silicate and carbonaceous dust mixed with gases
These detections confirm activity typical of active comets.
Importance of the data collected
3I/ATLAS analyzes expand knowledge about chemical diversity in interstellar comets. The organic compounds identified have structures common to terrestrial chemistry.
The preservation of ancient materials offers direct insight into conditions in the early universe. Observações complementary missions from other missions validate SPHEREx findings.
