View source for Astronomy:Critical-list minor planet

{{Short description|Numbered minor planet with uncertain position and orbit}}
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A '''critical-list minor planet''' (''critical list numbered object'' or ''critical object'') is a numbered [[Astronomy:Minor planet|minor planet]] for which existing measurements of the [[Physics:Orbit|orbit]] and [[Astronomy:Astrometry|position]] are especially in need of improvement.<ref name="Monet-1994" /> 

The [[Organization:International Astronomical Union|IAU]]'s [[Organization:Minor Planet Center|Minor Planet Center]] (MPC) regularly publishes a list of these critical objects in their ''Minor Planet Electronic Circular''.<ref name="MPC-MPEC" /> The list typically contains [[Astronomy:Asteroid|asteroid]]s that have been [[Astronomy:Observations of small Solar System bodies|observed]] at a small number of apparitions, especially on [[Astronomy:Opposition|opposition]], or that have not been adequately observed for more than 10 years, while other observatories create their own, customized lists.<ref name="Lowell" /> The MPC also lists currently observable critical objects on their website,<ref name="MPC-Observable" /> providing differently formatted lists of orbital elements to the worldwide astrometric community.<ref name="MPC-Observable-Elements" />

[[Astronomy:Lowell Observatory|Lowell Observatory]] publishes their own critical list, distinctly different from the MPC, instead focusing on objects with high [[Astronomy:Ephemeris|ephemeris]] uncertainty. Specifically, objects with computed ephemeris uncertainty greater than 2 arcseconds over the next 10 years, and objects whose orbits degrade significantly when temporally isolated observations are ignored, are included in the list.<ref name="Lowell" />

== List ==
{{As of|2023|08}}, the MPC includes 1,494 objects in their critical list. This list contains all critical objects within the first 50,000 numbered minor planets:<ref name="MPCORB" />
{{Div col|colwidth=22em}}
* [[Astronomy:1915 Quetzálcoatl|1915 Quetzálcoatl]]
* [[Astronomy:3362 Khufu|3362 Khufu]]
* [[Astronomy:5335 Damocles|5335 Damocles]]
* [[Astronomy:5381 Sekhmet|5381 Sekhmet]]
* [[Astronomy:(5590) 1990 VA|(5590) 1990 VA]]
* [[Astronomy:6489 Golevka|6489 Golevka]]
* [[Astronomy:7066 Nessus|7066 Nessus]]
* [[Astronomy:(7236) 1987 PA|(7236) 1987 PA]]
* [[Astronomy:10370 Hylonome|10370 Hylonome]]
* {{mpl|(15504) 1999 RG|33}}
* [[Astronomy:(15788) 1993 SB|(15788) 1993 SB]]
* {{mpl|(15807) 1994 GV|9}}
* [[Astronomy:(15809) 1994 JS|(15809) 1994 JS]]
* {{mpl|(15836) 1995 DA|2}}
* {{mpl|(15883) 1997 CR|29}}
* {{mpl|(16684) 1994 JQ|1}}
* {{mpl|(19255) 1994 VK|8}}
* {{mpl|(19299) 1996 SZ|4}}
* [[Astronomy:19521 Chaos|19521 Chaos]]
* {{mpl|(20108) 1995 QZ|9}}
* {{mpl|(20161) 1996 TR|66}}
* {{LoMP|20425|{{mp|(20425) 1998 VD|35}}}}
* [[Astronomy:20461 Dioretsa|20461 Dioretsa]]
* {{mpl|(24952) 1997 QJ|4}}
* {{mpl|(24978) 1998 HJ|151}}
* {{LoMP|26379|{{mp|(26379) 1999 HZ|1}}}}
* [[Astronomy:28978 Ixion|28978 Ixion]]
* {{mpl|(29981) 1999 TD|10}}
* {{LoMP|31662|{{mp|(31662) 1999 HP|11}}}}
* {{mpl|(33001) 1997 CU|29}}
* {{LoMP|35670|{{mp|(35670) 1998 SU|27}}}}
* [[Astronomy:38083 Rhadamanthus|38083 Rhadamanthus]]
* {{mpl|(40314) 1999 KR|16}}
* {{mpl|(45802) 2000 PV|29}}
* [[Astronomy:49036 Pelion|49036 Pelion]]
* {{mpl|(49673) 1999 RA|215}}
{{Div col end}}

== See also ==
* [[Astronomy:Distant minor planet|Distant minor planet]]
* [[Astronomy:Lost minor planet|Lost minor planet]]
* Unusual minor planet

== References ==
{{reflist|refs=

<ref name="Monet-1994">{{cite journal
  |last1      = Monet |first1 = A. K. B.
  |date       = December 1994
  |title      = CCD Astrometry of "Critical List" Minor Planets
  |journal    = American Astronomical Society Meeting Abstracts
  |volume     = 185
  |page       = 43.11
  |bibcode    = 1994AAS...185.4311M}}</ref>

<ref name="MPC-MPEC">{{cite web
  |title      = Minor Planet Electronic Circulars – Sample MPECs
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/iau/services/MPEC.html
  |access-date = 4 July 2020}}</ref>

<ref name="Lowell">{{cite web
  |title      = Critical Lists of Asteroids
  |publisher  = Lowell Observatory 
  |url        = https://asteroid.lowell.edu/critlists/legacy/
  |access-date = 29 November 2023}}</ref>

<ref name="MPC-Observable">{{cite web
  |title      = Observable Critical-List Minor Planets
  |work       = Minor Planet Center
  |url        = https://minorplanetcenter.net/iau/Ephemerides/CritList/index.html
  |access-date = 4 July 2020}}</ref>

<ref name="MPC-Observable-Elements">{{cite web
  |title      = Orbital Elements: Critical-List Minor Planets
  |work       = Minor Planet Center
  |url        = https://minorplanetcenter.net/iau/Ephemerides/CritList/SoftwareCritList.html
  |access-date = 4 July 2020}}</ref>

<ref name="MPCORB">{{cite web
  |title      = Data Available from the Minor Planet Center – MPCORB.DAT
  |work       = Minor Planet Center
  |date       = 26 June 2020
  |url        = https://minorplanetcenter.net/data
  |access-date = 15 August 2023}} ([https://www.minorplanetcenter.net/iau/info/MPOrbitFormat.html doc])</ref>

}} <!-- end of reflist -->

== External links ==
* [https://www.minorplanetcenter.net/mpec/J98/J98G21.html MPEC 1998-G21 : CRITICAL-LIST MINOR PLANETS], Minor Planet Circular (1998)
* [https://ntrs.nasa.gov/search.jsp?R=19940033930 Asteroid orbit determination using Bayesian probabilities], Karri Muinonen, Edward Bowell (1993)

{{Small Solar System bodies}}

[[Category:Minor planets]]

{{Sourceattribution|Critical-list minor planet}}