Masubi (volcano)

A volcanic plume has been observed at Masubi by various spacecraft starting with Voyager 1 in 1979, though it has not been persistent like similar Ionian volcanoes Amirani and Prometheus.

It was initially designated as Plume 8, but in 1979 the International Astronomical Union formally named it Masubi, after a Japanese fire god called Ho-Masubi.

[8] The Galileo spacecraft and ground-based astronomers observed volcanic activity at Masubi on several occasions in the late 1990s, but it was not a persistent thermal hotspot.

In each of these cases, the volcanic plumes emanated from different parts of Masubi Fluctus, providing further evidence that dust plumes like the one at Masubi result from the rapid sublimation of surficial sulfur dioxide frost by warm, advancing lava flow fronts, rather than erupting from the primary volcanic vent.

New Horizons images also highlighted the fact that the visibility of the older, 500-km long flow varies depending on the phase angle of the observation.

[3] A similar phase angle effect at Masubi Fluctus was also observed by Voyager and Galileo, though this was limited to longer visible wavelengths.