Sinope is a retrograde

irregular satellite In astronomy, an irregular moon, irregular satellite or irregular natural satellite is a natural satellite following a distant, inclined, and often eccentric and retrograde orbit. They have been captured by their parent planet, unlike regular s ...

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

discovered by

Seth Barnes Nicholson Seth Barnes Nicholson (November 12, 1891 – July 2, 1963) was an American astronomer. He worked at the Lick observatory in California, and is known for discovering several moons of Jupiter in the 20th century. Nicholson was born in Springfield, ...

at Lick Observatory in 1914, and is named after Sinope of

Greek mythology A major branch of classical mythology, Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the origin and nature of the world, the lives and activities ...

. Sinope did not receive its present name until 1975; (in which he declines to name the recently discovered satellites (pp. 93–94))IAUC 2846: ''Satellites of Jupiter''
1974 October (naming the moon) before then, it was simply known as . It was sometimes called " Hades" between 1955 and 1975.

Orbit

Sinope orbits Jupiter on a high-eccentricity and high-inclination retrograde orbit. Its orbit is continuously changing due to solar and planetary

perturbation Perturbation or perturb may refer to: * Perturbation theory, mathematical methods that give approximate solutions to problems that cannot be solved exactly * Perturbation (geology), changes in the nature of alluvial deposits over time * Perturbat ...

s. Sinope is believed to belong to the

Pasiphae group The Pasiphae group is a group of retrograde irregular satellites of Jupiter that follow similar orbits to Pasiphae and are thought to have a common origin. Their semi-major axes (distances from Jupiter) range between 22.8 and 24.1 million km (th ...

of retrograde irregular moons. Sheppard, S. S.; and Jewitt, D. C.
''An Abundant Population of Small Irregular Satellites Around Jupiter''
Nature, Vol. 423 (May 2003), pp. 261-263 However, given its mean inclination and different colour, Sinope could be also an independent object, captured independently, unrelated to the collision and break-up at the origin of the group. Grav, T.; Holman, M. J.; Gladman, B. J.; and Aksnes, K.
''Photometric Survey of the Irregular Satellites''
Icarus, Vol. 166 (2003), pp. 33-45 The diagram illustrates Sinope's orbital elements in relation to other satellites of the group. Sinope is also known to be in a

secular resonance A secular resonance is a type of orbital resonance between two bodies with synchronized precessional frequencies. In celestial mechanics, secular refers to the long-term motion of a system, and resonance is periods or frequencies being a simple n ...

with Jupiter, similar to Pasiphae. However, Sinope can drop out of this resonance and has periods of both resonant and non-resonant behaviour in time scales of 10⁷ years.

Physical characteristics

From measurements of its thermal emission, Sinope has an estimated diameter of . Sinope is red ( colour indices B−V=0.84, R−V=0.46), unlike Pasiphae, which is grey. Sinope's

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

spectrum A spectrum (plural ''spectra'' or ''spectrums'') is a condition that is not limited to a specific set of values but can vary, without gaps, across a continuum. The word was first used scientifically in optics to describe the rainbow of colors ...

is similar to those of

D-type asteroid D-type asteroids have a very low albedo and a featureless reddish spectrum. It has been suggested that they have a composition of organic-rich silicates, carbon and anhydrous silicates, possibly with water ice in their interiors. D-type asteroids ...

s but different from that of Pasiphae. These dissimilarities of the physical parameters suggest a different origin from the core members of the group.

References

External links

Sinope Profile
b
NASA's Solar System Exploration
(by

Scott S. Sheppard Scott Sander Sheppard (born 1977) is an American astronomer and a discoverer of numerous moons, comets and minor planets in the outer Solar System. He is an astronomer in the Department of Terrestrial Magnetism at the Carnegie Institution for Scie ...

) * Ephemeri
IAU-MPC NSES
{{DEFAULTSORT:Sinope (Moon) Moons of Jupiter Irregular satellites 19140721 Pasiphae group Moons with a retrograde orbit

Orbit

Physical characteristics

See also

References

External links