Origin of Molecular Oxygen in Comets: Current Knowledge and Perspectives

Area of Science:

• Planetary Science
• Cometary Science
• Astrochemistry

Background:

• The Rosetta spacecraft's ROSINA instrument detected molecular oxygen (O2) in comet 67P/Churyumov-Gerasimenko's coma.
• This marks the first definitive detection of O2 in any comet.
• The high abundance of O2, a reactive molecule with low interstellar prevalence, presents a significant scientific puzzle.

Purpose of the Study:

• To review and summarize existing hypotheses for the origin and production of molecular oxygen in comets.
• To consolidate current knowledge regarding cometary O2 formation mechanisms.
• To provide a comprehensive overview of the O2 puzzle in comet 67P/C-G.

Main Methods:

• Literature review of proposed O2 formation mechanisms.
• Analysis of ROSINA instrument data from Rosetta.
• Synthesis of theoretical models and observational evidence.

Main Results:

• Confirmed detection of unexpectedly high molecular oxygen abundances in comet 67P/C-G.
• Identified a wide range of proposed O2 origins, including in situ production, protosolar nebula, and primordial sources.
• Highlighted the ongoing debate and lack of consensus regarding the definitive source of cometary O2.

Conclusions:

• The presence of abundant O2 in comet 67P/C-G is a significant finding requiring further investigation.
• Multiple formation pathways are being considered, but a single, universally accepted explanation remains elusive.
• Understanding cometary O2 origins provides crucial insights into early solar system chemistry and evolution.