A simulated view of Larissa orbiting Neptune

Larissa (la-ris'-a, Greek Λάρῑσα) is the fifth of Neptune's known moons. It is also known as Neptune VII. It is named after Larissa, a lover of Poseidon (Neptune) in Greek mythology. Image File history File links Download high resolution version (1280x1005, 130 KB)A simulated view of Larissa orbiting Neptune. ... Image File history File links Download high resolution version (1280x1005, 130 KB)A simulated view of Larissa orbiting Neptune. ... A computer simulation or a computer model is a computer program which attempts to simulate an abstract model of a particular system. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ... Moons of solar system scaled to Earths Moon The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... Larissa (Greek: Λάρισα, Lárisa, (Turkish: YeniÅŸehr-i Fenar) is the capital city of the Thessaly periphery of Greece, and capital of the Larissa Prefecture. ... In Greek mythology, Poseidon (Ποσειδῶν) was the god of the sea. ... In Greek mythology, Poseidon (Ποσειδῶν) was the god of the sea. ... Greek mythology comprises the collected narratives of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ...

It was first discovered by Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky and David J. Tholen based on ground-based stellar occultation observations on May 24, 1981, and given the temporary designation S/1981 N 1. The announcement was made on January 15, 1982 (Science, vol. 215, pp. 289-291). The moon was not recovered until the Voyager 2 flyby in 1989 when it received the designation S/1989 N 2. Stephen P. Synnott announced (IAUC 4824) its recovery on August 2, 1989, speaking only of “10 frames taken over 5 days”, which gives a discovery date of sometime before July 28. Harold J. Reitsema is an astronomer who discovered Larissa, which is the fifth of Neptunes known moons. ... David James Tholen is an American astronomer at the Institute for Astronomy of the University of Hawaii, who specializes in planetary and solar system astronomy. ... May 24 is the 144th day of the year in the Gregorian calendar (145th in leap years). ... 1981 (MCMLXXXI) is a common year starting on Thursday of the Gregorian calendar. ... January 15 is the 15th day of the year in the Gregorian calendar. ... 1982 (MCMLXXXII) is a common year starting on Friday of the Gregorian calendar. ... The Voyager 2 spacecraft was launched in 1977. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... Stephen P. Synnott is a Voyager scientist who discovered several moons of Jupiter, Saturn, Uranus, and Neptune. ... August 2 is the 214th day of the year in the Gregorian Calendar (215th in leap years), with 151 days remaining. ... 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... July 28 is the 209th day (210th in leap years) of the year in the Gregorian Calendar, with 156 days remaining. ...

Larissa is irregular (non-spherical) in shape and appears to be heavily cratered, with no sign of any geological modification. Little else is known about it. Since the Larissean orbit is below Neptune's synchronous orbit radius it is slowly decaying due to tidal forces and will one day break up into a planetary ring or enter Neptune's atmosphere. This article is about impact craters, also known as meteor craters. ... Comet Shoemaker-Levy 9 after breaking up under the influence of Jupiters tidal forces. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ...

• Orbital radius: 73,548 km
• Diameter: 216×204×168 km
• Mass: 4.9×10¹⁸ kg
• Estimated density: 1.3 g/cm³
• Orbital period: 0.555 days
• Orbital inclination: 0.242° (to Neptune's equator), 0.205° (to the local Laplace plane), 28.63° (to the ecliptic)

The Laplace plane is defined as the mean plane occupied by the orbit of a satellite during a precession cycle. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ...

External links

• IAU Circular 3608 describing the discovery of S/1981 N 1
• IAU Circular 4824 describing the discovery of S/1989 N 2, 3, and 4
• The Nine Planets: Larissa
• Views of the Solar System: Larissa

References

• Gazetteer of Planetary Nomenclature