NASA’s Telescópio Espacial James Webb has recorded the first chemical signature of methane in an interstellar object. The detection occurred during observations of comet 3I/ATLAS in December. The comet, which came from outside the solar system, passed through Sol and is now heading back to interstellar space.
Cientistas used the MIRI instrument to capture the data. The measurements took place on two different dates, while the object was moving away from Sol. The discovery provides information about the composition of materials formed in another planetary system.
Detecção of methane occurs after passing through Sol
James Webb observed comet 3I/ATLAS between December 15th and 16th. At the time, the object was approximately 329 million kilometers from Sol. A second observation came on December 27, with the comet 379 million kilometers away.
Methane appeared late. Isso indicates that the gas was buried in deeper layers of the core. The heat from the solar approach released the material protected from previous sublimation. Methane is highly volatile and easily changes from a solid to a gaseous state.
The amount of methane in relation to water surprised researchers. The value is greater than that seen in most comets in the solar system. Essa proportion points to a formation environment different from that which gave rise to local comets.
- Comet 3I/ATLAS poses no threat to Terra
- Observações combines data from multiple NASA instruments
- The object was discovered in the summer of 2025
- Equipes monitor decline in gaseous activity
Cometa maintains high carbon dioxide level
The measurements also confirmed that 3I/ATLAS releases a lot of carbon dioxide compared to water. The pattern differs from that seen in most comets formed here. Scientists interpret this as evidence of origin in a region with different chemical conditions.
Carbon dioxide and methane appear more concentrated near the core. Já water vapor spreads further across the coma. The distribution helps understand how gases escape from the icy object.
Produção of gas falls as comet moves away
The comet’s activity decreased markedly between the two observations. Water production fell faster than that of other gases. Esse behavior is expected, as the surface cools and releases less vaporized ice with increasing distance from Sol.
Comet 3I/ATLAS completes its passage through the solar system. Ele will not return in an observable time. Therefore, the current observations are the last chances to study its composition up close.
Instrumento MIRI enables detailed analysis
MIRI, or Instrumento from Infravermelho Médio, breaks down light into specific wavelengths. The equipment generated spectra that identified the gases present. Ele also mapped the distribution around the nucleus.
Imagens show the comet with contours that highlight the positions of the different compounds. Water dominates wider areas, while carbon dioxide and methane are close to the center.
Descoberta reinforces study of interstellar objects
3I/ATLAS is the third interstellar object confirmed to visit the solar system. Diferente of local comets, it brings material from another region of the galaxy. James Webb analyzes contribute to understanding planetary formation processes beyond our Sol.
Pesquisadores from several institutions participate in the effort. The results were published in the journal The Astrophysical Journal Letters. The work integrates data from other telescopes, such as Hubble.
Observations continue to provide clues about chemical diversity in the universe. Cada new data helps compare what happens here with what happens in distant systems. Comet 3I/ATLAS continues its trajectory and will soon disappear into interstellar space.