Clathrate hydrate formation in amorphous cometary ice analogs in vacuo

Area of Science:

• Cosmochemistry
• Planetary Science
• Astrobiology

Background:

• Clathrate hydrates in cometary ice are hypothesized to explain unusual gas release and volatile retention.
• Formation mechanisms for clathrate hydrates in low-pressure environments (interstellar clouds, solar nebula, cometary ices) remain poorly understood.

Purpose of the Study:

• To investigate the formation of clathrate hydrates in amorphous ices under low-pressure conditions.
• To elucidate the solid-state processes involved in clathrate hydrate formation relevant to cometary ices.

Main Methods:

• Experiments utilizing a modified electron microscope.
• Controlled warming of vapor-deposited amorphous ices in a vacuum (in vacuo).

Main Results:

• Clathrate hydrates were observed to form via solid-state rearrangements during the warming of amorphous ices.
• These rearrangements resulted in phase separations and the development of microporous textures.

Conclusions:

• Solid-state rearrangements provide a viable mechanism for clathrate hydrate formation in low-pressure astrophysical environments.
• The observed phenomena offer explanations for anomalous cometary behaviors, including gas release and volatile retention.