Cordelia is the
innermost known moon of
Uranus
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (mythology), Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars (mythology), Mars), grandfather ...
. It was discovered from the images taken by ''
Voyager 2
''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, ''Voyager 1'', on a ...
'' on January 20, 1986, and was given the temporary designation S/1986 U 7.
It was not detected again until the
Hubble Space Telescope
The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...
observed it in 1997.
Cordelia takes its name from the youngest daughter of Lear in
William Shakespeare
William Shakespeare ( 26 April 1564 – 23 April 1616) was an English playwright, poet and actor. He is widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's nation ...
's ''
King Lear
''King Lear'' is a tragedy written by William Shakespeare.
It is based on the mythological Leir of Britain. King Lear, in preparation for his old age, divides his power and land between two of his daughters. He becomes destitute and insane an ...
.'' It is also designated Uranus VI.
Other than its orbit,
radius of 20 km
and
geometric albedo
In astronomy, the geometric albedo of a celestial body is the ratio of its actual brightness as seen from the light source (i.e. at zero phase angle) to that of an ''idealized'' flat, fully reflecting, diffusively scattering ( Lambertian) disk w ...
of 0.08
virtually nothing is known about it. In the Voyager 2 images Cordelia appears as an elongated object with its major axis pointing towards Uranus. The ratio of axes of Cordelia's prolate spheroid is 0.7 ± 0.2.
Cordelia acts as the inner
shepherd satellite
A ring system is a disc or ring, orbiting an astronomical object, that is composed of solid material such as dust and moonlets, and is a common component of satellite systems around giant planets. A ring system around a planet is also known a ...
for Uranus'
ε ring.
Cordelia's orbit is within Uranus' synchronous orbit radius, and is therefore slowly decaying due to
tidal deceleration
Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite (e.g. the Moon) and the primary planet that it orbits (e.g. Earth). The acceleration causes a gradual recession of a satellite in a prograde orbit away from ...
.
Cordelia is very close to a 5:3
orbital resonance
In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. Most commonly, this relationsh ...
with
Rosalind.
See also
*
Moons of Uranus
Uranus, the seventh planet of the Solar System, has 27 known moons, most of which are named after characters that appear in, or are mentioned in, the works of William Shakespeare and Alexander Pope. Uranus's moons are divided into three groups: t ...
References
Explanatory notes
Citations
External links
Cordelia Profileb
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 ...
)
{{DEFAULTSORT:Cordelia (Moon)
Moons of Uranus
19860120
Moons with a prograde orbit
King Lear