Prometheus is an active

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Io. It is located on Io's hemisphere facing away from Jupiter at .

Description

Prometheus consists of a volcanic pit named Prometheus Patera and a compound lava flow, all surrounded by reddish

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

and circular, bright

sulfur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...

() volcanic plume deposits. The volcano was first observed in images acquired by the ''

Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and the interstellar medium, interstellar space beyond the Sun's heliosphere. It was launched 16 days afte ...

'' spacecraft in March 1979. Later that year, the

International Astronomical Union The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

named this feature after a

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

fire god,

Prometheus In Greek mythology, Prometheus (; , , possibly meaning "forethought")Smith"Prometheus". is a Titans, Titan. He is best known for defying the Olympian gods by taking theft of fire, fire from them and giving it to humanity in the form of technol ...

. Prometheus is the site of a volcanic eruption that has been ongoing since at least the ''Voyager 1'' encounter in 1979. Between the Voyager encounters and the first observations by ''

Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

'', a flow field was emplaced. Later ''Galileo'' observations of this flow field revealed numerous small breakouts, particularly on the western end of the flow field. Prometheus is the site of two volcanic eruption plumes: a small, sulfur-rich plume erupting from the magma-source vent at the eastern end of the flow field and a , -rich dust plume erupting from the active flow front at the other end. The former forms a diffuse, red deposit to the east of the Prometheus flow field. The latter forms a bright, circular deposit surrounding the entire volcano and lava flow. The -rich plume is generated as lava at the western end of the flow field covers sulfur dioxide frost, heating and vaporizing it. This is accomplished at multiple breakouts, generating gas and dust for the visible dust plume. Prometheus' plume has been observed by both ''Voyager'' spacecraft, ''Galileo'', and ''

New Horizons ''New Horizons'' is an Interplanetary spaceflight, interplanetary space probe launched as a part of NASA's New Frontiers program. Engineered by the Johns Hopkins University Applied Physics Laboratory (APL) and the Southwest Research Institut ...

'', at every appropriate imaging opportunity.

References

{{Voyager program Volcanoes of Io (moon) Prometheus Active volcanoes