2003 AZ84
Encyclopedia
, also written as 2003 AZ84, is a plutino
, like Pluto
, in a 2:3 resonance with Neptune
. It is very likely a dwarf planet
. It was discovered on January 13, 2003 by C. Trujillo and M. Brown
using the Samuel Oschin telescope
in the Palomar Observatory
. Light-curve-amplitude analysis shows only small deviations, suggesting that is a spheroid with small albedo spots and hence a dwarf planet.
, which means that it is in a 3:2 orbital resonance
with Neptune
, similar to that of Pluto
. It orbits the Sun in just over 247 Earth years.
2003 AZ84 is currently 45.3 AU from the Sun and came to aphelion
(farthest distance from the Sun) in 1982. It will come to perihelion
in 2107. Simulations by the Deep Ecliptic Survey
(DES) show that over the next 10 million years 2003 AZ84 will not come closer (qmin) than 31.6 AU from the Sun (it will stay farther away than Neptune).
The rotation period of 2003 AZ84 is not exactly known, but the most likely value is about 6.7 hours.
has estimated it to have a size of , while an analysis of a combination of Spitzer and Hershel data yielded a somewhat higher estimate of . Due to its large size 2003 AZ84 qualifies as a plutoid candidate. Its mass is unknown, but a reasonable estimate is 3–5 kg.
The spectra and colors of 2003 AZ84 are very similar to those of Orcus
, another large planetoid in 3:2 resonance with Neptune. Both bodies have a flat featureless spectrum in the visible and moderately strong water ice absorption bands in the near-infrared, although 2003 AZ84 has a lower albedo. Both bodies also have a weak absorption band near 2.3 μm, which may be caused by ammonia
hydrate or methane
ice.
A stellar occultation in 2010 measured a single chord
of 573±21 km. But this is only a lower limit for the diameter of 2003 AZ84 as the chord may not have passed through the center of the body.
of was reported in IAUC 8812 on 22 February 2007. The orbit of this satellite has yet to be determined, but was measured with a separation of 0.22 arcsec
and an apparent magnitude
difference of 5.0. It is estimated to be about 68 ± 20 km in diameter.
Plutino
In astronomy, a plutino is a trans-Neptunian object in 2:3 mean motion resonance with Neptune. For every 2 orbits that a plutino makes, Neptune orbits 3 times. Plutinos are named after Pluto, which follows an orbit trapped in the same resonance, with the Italian diminutive suffix -ino...
, like Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
, in a 2:3 resonance with Neptune
Resonant trans-Neptunian object
In astronomy, a resonant trans-Neptunian object is a trans-Neptunian object in mean motion orbital resonance with Neptune. The orbital periods of the resonant objects are in a simple integer relations with the period of Neptune e.g. 1:2, 2:3 etc...
. It is very likely a dwarf planet
Dwarf planet
A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
. It was discovered on January 13, 2003 by C. Trujillo and M. Brown
Michael E. Brown
Michael E. Brown has been a professor of planetary astronomy at the California Institute of Technology since 2003....
using the Samuel Oschin telescope
Samuel Oschin telescope
The Samuel Oschin telescope is a 48-inch aperture Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch mirror. The instrument is strictly a camera; there is no provision for an eyepiece to look...
in the Palomar Observatory
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
. Light-curve-amplitude analysis shows only small deviations, suggesting that is a spheroid with small albedo spots and hence a dwarf planet.
Orbit
It is classified as a plutinoPlutino
In astronomy, a plutino is a trans-Neptunian object in 2:3 mean motion resonance with Neptune. For every 2 orbits that a plutino makes, Neptune orbits 3 times. Plutinos are named after Pluto, which follows an orbit trapped in the same resonance, with the Italian diminutive suffix -ino...
, which means that it is in a 3:2 orbital resonance
Orbital resonance
In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other, usually due to their orbital periods being related by a ratio of two small integers. Orbital resonances greatly enhance the mutual gravitational influence of...
with Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
, similar to that of Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
. It orbits the Sun in just over 247 Earth years.
2003 AZ84 is currently 45.3 AU from the Sun and came to aphelion
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
(farthest distance from the Sun) in 1982. It will come to perihelion
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
in 2107. Simulations by the Deep Ecliptic Survey
Deep Ecliptic Survey
The Deep Ecliptic Survey is a project to find Kuiper belt objects , using the facilities of the National Optical Astronomy Observatory .The principal investigator is Bob Millis....
(DES) show that over the next 10 million years 2003 AZ84 will not come closer (qmin) than 31.6 AU from the Sun (it will stay farther away than Neptune).
The rotation period of 2003 AZ84 is not exactly known, but the most likely value is about 6.7 hours.
Physical characteristics
The Spitzer Space TelescopeSpitzer Space Telescope
The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...
has estimated it to have a size of , while an analysis of a combination of Spitzer and Hershel data yielded a somewhat higher estimate of . Due to its large size 2003 AZ84 qualifies as a plutoid candidate. Its mass is unknown, but a reasonable estimate is 3–5 kg.
The spectra and colors of 2003 AZ84 are very similar to those of Orcus
90482 Orcus
90482 Orcus is a trans-Neptunian object in the Kuiper belt with a large moon. It was discovered on February 17, 2004 by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. Precovery images as early as November 8, 1951 were later identified...
, another large planetoid in 3:2 resonance with Neptune. Both bodies have a flat featureless spectrum in the visible and moderately strong water ice absorption bands in the near-infrared, although 2003 AZ84 has a lower albedo. Both bodies also have a weak absorption band near 2.3 μm, which may be caused by ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
hydrate or methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
ice.
A stellar occultation in 2010 measured a single chord
Chord (astronomy)
In the field of astronomy the term chord typically refers to a line crossing an object which is formed during an occultation event. By taking accurate measurements of the start and end times of the event, in conjunction with the known location of the observer and the object's orbit, the length of...
of 573±21 km. But this is only a lower limit for the diameter of 2003 AZ84 as the chord may not have passed through the center of the body.
Satellite
The discovery of a satelliteAsteroid moon
A minor planet moon is an astronomical body that orbits a minor planet as its natural satellite. It is thought that many asteroids and Kuiper belt objects may possess moons, in some cases quite substantial in size...
of was reported in IAUC 8812 on 22 February 2007. The orbit of this satellite has yet to be determined, but was measured with a separation of 0.22 arcsec
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
and an apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
difference of 5.0. It is estimated to be about 68 ± 20 km in diameter.
External links
- Orbital simulation from JPL (Java) / Ephemeris
- (208996) 2003 AZ84 Precovery Images