Carme is a retrograde irregular satellite of Jupiter. Carme is the second largest retrograde (after Pasiphaë) and third largest irregular satellite after Himalia, Elara and Pasiphaë.
Carme is the 10th largest moon of Jupiter and 67th largest moon in the Solar System currently known.
Discovery
Carme was discovered by Seth Barnes Nicholson with the 100-inch Hooker telescope at the Mount Wilson Observatory in California on 30th July 1938.
Naming
Carme did not receive its present name until 1975. Nicholson himself declined to propose names. Before then, it was simply known as Jupiter XI. It was sometimes called "Pan" between 1955 and 1975 (Pan is now the name of a satellite of Saturn).
Carme the moon is named after the mythological Carme, mother by Zeus of Britomartis, a Cretan goddess.
Carme, the Latinized form of Greek Karmê ("shearer"), was a female Cretan spirit who assisted the grain harvest of Demeter's Cretan predecessor. According to the Olympian mythology, she was the mother, by Zeus, of the virginal huntress Britomartis, also called Diktynna, whom she bore at Kaino.
Stats
Diameter (mean): 46 km
Semi-major axis: 23,197,992 km
Orbital Period: -721.82 days
Group: Carme group
Orbit
Carme gives its name to the Carme group, made up of irregular retrograde moons orbiting Jupiter at a distance ranging between 23 and 24 Gm and at an inclination of about 165°. Carme's orbital elements are as of January 2000 and they are continuously changing due to solar and planetary perturbations.
Carme is the largest member of the Carme group, a family of Jovian moons which have similar orbits and appearance and are therefore thought to have a common origin.
Formation
Carme was probably a D-type asteroid (possibly from the Hilda family or the Jupiter Trojans) that suffered a collision, which broke off a number of pieces, either before or after being captured by Jupiter's gravity. Those pieces became the other 16 moons in the Carme group.
Moons in Carme group all are very similar in color -- light red -- except for Kalyke, which is considerably redder than the others. All of these characteristics support the idea that the Carme moons began as a captured asteroid, rather than forming as part of the original Jupiter system.
Physical Characteristics
None of the Carme moons is massive enough to pull itself into a sphere, so they are probably all irregularly shaped.
Tuesday, 31 January 2012
Monday, 30 January 2012
20th Largest Asteroid, 375 Ursula
375 Ursula is a large main belt asteroid and is the 20th largest asteroid currently known.
Discovery
Ursula was discovered by Auguste Honoré Charlois on September 18, 1893, in Nice.
Naming
Any reference of its name to a person or an occurrence is unknown.
Stats
Diameter (mean): 216 km
Aphelion: 3.46 AU
Perihelion: 2.79 AU
Semi-major axis: 3.123 AU
Orbital Period: 5.52 years
Rotation period: 16.83 hrs
Date discovered: 1893.9.18
Class: C
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Star Occultation
A value of 216 +/- 10 km for the mean diameter of Ursula is given, based on photometric measurements and observations of the occultation of AG + 39 deg 303, a K-type star of visual magnitude 8.8, by 375 Ursula on November 15, 1982.
From the occultation diameter and the absolute visual magnitudes presented, the visual geometric albedo of Ursula is determined to be 0.032, similar to the value typical of C-type asteroids.
Discovery
Ursula was discovered by Auguste Honoré Charlois on September 18, 1893, in Nice.
Naming
Any reference of its name to a person or an occurrence is unknown.
Stats
Diameter (mean): 216 km
Aphelion: 3.46 AU
Perihelion: 2.79 AU
Semi-major axis: 3.123 AU
Orbital Period: 5.52 years
Rotation period: 16.83 hrs
Date discovered: 1893.9.18
Class: C
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Star Occultation
A value of 216 +/- 10 km for the mean diameter of Ursula is given, based on photometric measurements and observations of the occultation of AG + 39 deg 303, a K-type star of visual magnitude 8.8, by 375 Ursula on November 15, 1982.
From the occultation diameter and the absolute visual magnitudes presented, the visual geometric albedo of Ursula is determined to be 0.032, similar to the value typical of C-type asteroids.
Sunday, 29 January 2012
19th Largest Asteroid, 48 Doris
48 Doris is a large main belt asteroid, with a diameter of around 222 km. Doris is the 19th largest asteroid currently known.
Discovery
Doris was discovered by Hermann Goldschmidt on September 19, 1857 from his balcony in Paris.
Naming
To find a name for the asteroid, Jacques Babinet of the Academy of Sciences created a shortlist and asked the geologist Élie de Beaumont to make the selection. De Beaumont chose Doris, after an Oceanid in Greek mythology.
Doris, an Oceanid, was a sea nymph in Greek mythology, whose name represented the bounty of the sea. She was the daughter of Oceanus and Tethys and the wife of Nereus. She was also aunt to Atlas, the titan who was made to carry the sky upon his shoulders, whose mother Clymene was a sister of Doris.
Stats
Diameter (mean): 221.8 km
Aphelion: 3.343 AU
Perihelion: 2.88 AU
Semi-major axis: 3.114 AU
Orbital Period: 5.49 years
Rotation period: 11.89 hrs
Date discovered: 1857.9.19
Class: C
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Star Occultation
An occultation (SAO 118832) on March 19, 1981, suggested a diameter of 219±25 km for Doris.
Observations of an occultation (SAO 161849) on October 14, 1999, using four well-placed chords, indicate an ellipsoid of 278×142 km and that Doris is an extremely irregular shaped object.
Discovery
Doris was discovered by Hermann Goldschmidt on September 19, 1857 from his balcony in Paris.
Naming
To find a name for the asteroid, Jacques Babinet of the Academy of Sciences created a shortlist and asked the geologist Élie de Beaumont to make the selection. De Beaumont chose Doris, after an Oceanid in Greek mythology.
Doris, an Oceanid, was a sea nymph in Greek mythology, whose name represented the bounty of the sea. She was the daughter of Oceanus and Tethys and the wife of Nereus. She was also aunt to Atlas, the titan who was made to carry the sky upon his shoulders, whose mother Clymene was a sister of Doris.
Stats
Diameter (mean): 221.8 km
Aphelion: 3.343 AU
Perihelion: 2.88 AU
Semi-major axis: 3.114 AU
Orbital Period: 5.49 years
Rotation period: 11.89 hrs
Date discovered: 1857.9.19
Class: C
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Star Occultation
An occultation (SAO 118832) on March 19, 1981, suggested a diameter of 219±25 km for Doris.
Observations of an occultation (SAO 161849) on October 14, 1999, using four well-placed chords, indicate an ellipsoid of 278×142 km and that Doris is an extremely irregular shaped object.
18th Largest Asteroid, 532 Herculina
532 Herculina is a large main belt asteroid, with a diameter of around 222 km. Herculina is the 18th largest asteroid currently known.
Discovery
Herculina was discovered on April 20, 1904, by Max Wolf in Heidelberg.
Naming
Herculina was initially catalogued as 1904 NY.
The origin of Herculina's name was lost. The asteroid may be named after the mythical Hercules, or after an unknown woman of that name. The bulk of the asteroids discovered by Wolf around this date were named for characters in operas, but if this name was also drawn from such a source, no explanation has been recorded.
Stats
Diameter (mean): 222 km
Aphelion: 3.26 AU
Perihelion: 2.278 AU
Semi-major axis: 2.77 AU
Orbital Period: 4.61 years
Rotation period: 9.405 hrs
Date discovered: 1904.4.20
Class: S
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Physical characteristics
Herculina has often been noted for its complex lightcurves, which made determination of its shape and rotation somewhat difficult.
Recent modelling in 2002 of photometric data indicates that Herculina is not spherical, but a blocky shape not unlike a battered cuboid - or, as the analysis described it, it "resembles a toaster". This analysis indicates the presence of multiple large craters, but no major variation in albedo. The approximate ratios of the axes were suggested as 1:1.1:1.3, broadly consistent with earlier models if slightly more elongated.
Satellite (S/1978(532)1) ?
Following anomalous observations during an occultation of the star SAO 120774 in 1978, Herculina became the first asteroid to be "confirmed" to have an asteroid moon. A satellite of about 45 km orbiting at a distance of about 1,000 km from Herculina.
However, careful examination in 1993, using the Hubble Space Telescope, failed to locate the moon.
Discovery
Herculina was discovered on April 20, 1904, by Max Wolf in Heidelberg.
Naming
Herculina was initially catalogued as 1904 NY.
The origin of Herculina's name was lost. The asteroid may be named after the mythical Hercules, or after an unknown woman of that name. The bulk of the asteroids discovered by Wolf around this date were named for characters in operas, but if this name was also drawn from such a source, no explanation has been recorded.
Stats
Diameter (mean): 222 km
Aphelion: 3.26 AU
Perihelion: 2.278 AU
Semi-major axis: 2.77 AU
Orbital Period: 4.61 years
Rotation period: 9.405 hrs
Date discovered: 1904.4.20
Class: S
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Physical characteristics
Herculina has often been noted for its complex lightcurves, which made determination of its shape and rotation somewhat difficult.
Recent modelling in 2002 of photometric data indicates that Herculina is not spherical, but a blocky shape not unlike a battered cuboid - or, as the analysis described it, it "resembles a toaster". This analysis indicates the presence of multiple large craters, but no major variation in albedo. The approximate ratios of the axes were suggested as 1:1.1:1.3, broadly consistent with earlier models if slightly more elongated.
Satellite (S/1978(532)1) ?
Following anomalous observations during an occultation of the star SAO 120774 in 1978, Herculina became the first asteroid to be "confirmed" to have an asteroid moon. A satellite of about 45 km orbiting at a distance of about 1,000 km from Herculina.
However, careful examination in 1993, using the Hubble Space Telescope, failed to locate the moon.
Saturday, 28 January 2012
17th Largest Asteroid, 19 Fortuna
Discovery
Fortuna was discovered by John Russell Hind on August 22, 1852 in London.
Naming
Fortuna the asteroid was named after Fortuna, the Roman goddess of luck.
Fortuna (equivalent to the Greek goddess Tyche) was the goddess of fortune and personification of luck in Roman religion. She might bring good luck or bad: she could be represented as veiled and blind, as in modern depictions of Justice, and came to represent life's capriciousness.
Stats
Diameter (mean): 225 km
Aphelion: 2.831 AU
Perihelion: 2.057 AU
Semi-major axis: 2.442 AU
Orbital Period: 3.82 years
Rotation period: 7.443 hrs
Date discovered: 1852.8.22
Class: G
Type: Main-belt Asteroid
Physical Characteristics
Fortuna has one of the darkest known geometric albedos for an asteroid over 150 km in diameter. Its albedo has been measured at 0.028 and 0.037.
Fortuna has a composition similar to 1 Ceres: a darkly colored surface that is heavily space-weathered with the composition of primitive organic compounds, including tholins.
Friday, 27 January 2012
16th Largest Asteroid, 451 Patientia
451 Patientia is an asteroid of the main asteroid belt and with a diameter of 225 km is one of the larger asteroids in the belt. Patientia is the 16th largest asteroids currently known.
Discovery
Patientia was discovered by Auguste Honoré Charlois on December 4, 1899 in Nice.
Naming
The asteroid's provisional designation was 1899 EY. It was named after "patience", as Patientia means "patience" in Latin.
Stats
Diameter (mean): 225 km
Aphelion: 3.295 AU
Perihelion: 2.823 AU
Semi-major axis: 3.065 AU
Orbital Period: 5.37 years
Rotation period: 9.727 hrs
Date discovered: 1899.12.4
Class: ?
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Orbit
Patientia regularly reaches 11th magnitude in brightness. In January 11th, 2013 and December 12th, 2017, when in favorable oppositions, Patientia will be at magnitudes 10.7 and 10.4 respectively. This is very bright for a later-discovered asteroid.
Discovery
Patientia was discovered by Auguste Honoré Charlois on December 4, 1899 in Nice.
Naming
The asteroid's provisional designation was 1899 EY. It was named after "patience", as Patientia means "patience" in Latin.
Stats
Diameter (mean): 225 km
Aphelion: 3.295 AU
Perihelion: 2.823 AU
Semi-major axis: 3.065 AU
Orbital Period: 5.37 years
Rotation period: 9.727 hrs
Date discovered: 1899.12.4
Class: ?
Type: Main-belt Asteroid
(data from JPL Small-Body Database)
Orbit
Patientia regularly reaches 11th magnitude in brightness. In January 11th, 2013 and December 12th, 2017, when in favorable oppositions, Patientia will be at magnitudes 10.7 and 10.4 respectively. This is very bright for a later-discovered asteroid.
Sunday, 22 January 2012
9th Largest Moon of Neptune - Halimede (9th Moon outwards from Neptune)
Halimede is a retrograde irregular satellite of Neptune. Halimede is the 9th overall largest satellite of Neptune and 61th largest moon in the Solar System currently known.
Discovery
Matthew J. Holman, Harvard-Smithsonian Center for Astrophysics (CfA); John J. Kavelaars, National Research Council of Canada; T. Grav, University of Oslo and CfA; and W. Fraser and Dan Milisavljevic, McMaster University, reported the discovery of three satellites of Neptune on CCD images obtained in 14 August 2002 with the 4-m Blanco telescope at Cerro Tololo.
Naming
The moon was given the temporary designation S/2002 N1.
Halimede the moon is named after one of the Nereids, the fifty daughters of Nereus and Doris.
Stats
Diameter (mean): 62 km
Semi-major axis: 16,611,000 km
Orbital Period: 1879.08 days
Rotation Period: ?
Orbit
Halimede has the second most eccentric (0.2646) and third most inclined (112.712°) orbit around Neptune.
Formation
Given the very similar colour of the satellite to that of Nereid together with the high probability of collision in the past lifespan of the Solar System, it has been suggested that the satellite could be a fragment of Nereid.
Physical characteristics
Little is known about Halimede.
Halimede is about 62 kilometers in diameter (assuming an albedo of 0.04) and appears neutral (grey) in the visible light.
Discovery
Matthew J. Holman, Harvard-Smithsonian Center for Astrophysics (CfA); John J. Kavelaars, National Research Council of Canada; T. Grav, University of Oslo and CfA; and W. Fraser and Dan Milisavljevic, McMaster University, reported the discovery of three satellites of Neptune on CCD images obtained in 14 August 2002 with the 4-m Blanco telescope at Cerro Tololo.
Naming
The moon was given the temporary designation S/2002 N1.
Halimede the moon is named after one of the Nereids, the fifty daughters of Nereus and Doris.
Stats
Diameter (mean): 62 km
Semi-major axis: 16,611,000 km
Orbital Period: 1879.08 days
Rotation Period: ?
Orbit
Halimede has the second most eccentric (0.2646) and third most inclined (112.712°) orbit around Neptune.
Formation
Given the very similar colour of the satellite to that of Nereid together with the high probability of collision in the past lifespan of the Solar System, it has been suggested that the satellite could be a fragment of Nereid.
Physical characteristics
Little is known about Halimede.
Halimede is about 62 kilometers in diameter (assuming an albedo of 0.04) and appears neutral (grey) in the visible light.
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