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A critical-list minor planet (''critical list numbered object'' or ''critical object'') is a numbered
minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term '' ...
whose
orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such a ...
and
position
Position often refers to:
* Position (geometry), the spatial location (rather than orientation) of an entity
* Position, a job or occupation
Position may also refer to:
Games and recreation
* Position (poker), location relative to the dealer
* ...
is especially in need of improvement.
The
IAU
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...
's
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory.
Function
...
(MPC) regularly publishes a list of these critical objects in their ''
Minor Planet Electronic Circular
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory.
Function
T ...
''.
The list typically contains
asteroid
An asteroid is a minor planet of the Solar System#Inner solar system, inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic o ...
s that have been
observed at a small number of apparitions, especially on
opposition
Opposition may refer to:
Arts and media
* ''Opposition'' (Altars EP), 2011 EP by Christian metalcore band Altars
* The Opposition (band), a London post-punk band
* '' The Opposition with Jordan Klepper'', a late-night television series on Com ...
, or that have not been adequately observed for more than 10 years, while other observatories create their own, customized lists.
The MPC also lists currently observable critical objects on their website,
providing differently formatted lists of
orbital element
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same ...
s to the worldwide
astrometric
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
Histor ...
community.
, the MPC includes more than a thousand objects in their critical list, half of them being either
near-Earth asteroids
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
or
distant minor planets which account for 674 and 192 critical objects, respectively.
List
The lowest numbered critical-list objects are:
*
1915 Quetzálcoatl
*
2135 Aristaeus
2135 Aristaeus (1977 HA) is an Apollo asteroid discovered on April 17, 1977, by E. F. Helin and S. J. Bus at Palomar Observatory. It is named for Aristaeus, the son of Apollo and the nymph Cyrene.
2135 Aristaeus is a potentially hazardous ast ...
*
3362 Khufu
3362 Khufu is a near-Earth asteroid. It was discovered by R. Scott Dunbar and Maria A. Barucci at the Palomar Observatory in San Diego County, California, on 30 August 1984. Its provisional designation was 1984 QA. It is named after Khufu, an ...
*
3753 Cruithne
3753 Cruithne is a Q-type, Aten asteroid in orbit around the Sun in 1:1 orbital resonance with Earth, making it a co-orbital object. It is an asteroid that, relative to Earth, orbits the Sun in a bean-shaped orbit that effectively describes ...
*
(4688) 1980 WF
*
5335 Damocles
*
(5590) 1990 VA
*
7066 Nessus
*
(8014) 1990 MF
*
10370 Hylonome
*
14827 Hypnos
*
*
(15789) 1993 SC
(15789) 1993 SC is a trans-Neptunian object of the plutino class. The discovery was made in 1993 at the La Palma Observatory with the Isaac Newton Telescope. It was the second plutino to receive an MPC number.
KBO's found in 1993 include: (15788) ...
*
*
(15809) 1994 JS
*
*
*
*
*
19521 Chaos
19521 Chaos is a cubewano, a Kuiper-belt object not in resonance with any planet. Chaos was discovered in 1998 by the Deep Ecliptic Survey with Kitt Peak's 4 m telescope. Its albedo is , making it, with its absolute magnitude (H) of 4.8, ...
*
*
*
*
20461 Dioretsa
20461 Dioretsa is a centaur and damocloid on a retrograde, cometary-like orbit from the outer Solar System. It was discovered on 8 June 1999, by members of the LINEAR team at the Lincoln Laboratory Experimental Test Site near Socorro, New Mexi ...
See also
*
Distant minor planet
*
Lost minor planet
A minor planet is "lost" when today's observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observat ...
*
Unusual minor planet
References
External links
MPEC 1998-G21 : CRITICAL-LIST MINOR PLANETS Minor Planet Circular (1998)
Asteroid orbit determination using Bayesian probabilities Karri Muinonen, Edward Bowell (1993)
{{Small Solar System bodies
Minor planets