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{{Short description|International astronomical organization}}
{{Use mdy dates|date=March 2025}}

The '''Minor Planet Center''' ('''MPC''') is the official body for observing and reporting on [[minor planet]]s under the auspices of the [[International Astronomical Union]] (IAU). Founded in 1947, it operates at the [[Smithsonian Astrophysical Observatory]].

==Function==
The Minor Planet Center is the official worldwide organization in charge of collecting observational data for [[minor planet]]s (such as [[asteroid]]s), calculating their [[orbit]]s and publishing this information via the ''[[#Publications|Minor Planet Circulars]]''. Under the auspices of the [[International Astronomical Union]] (IAU), it operates at the [[Smithsonian Astrophysical Observatory]], which is part of the [[Center for Astrophysics]] along with the [[Harvard College Observatory]].<ref name="IAU-Centres" />

The MPC runs a number of free online services for observers to assist them in observing minor planets and comets.  The complete catalogue of minor planet orbits (sometimes referred to as the "Minor Planet Catalogue") may also be freely downloaded. In addition to [[astrometric]] data, the MPC collects light curve photometry of minor planets. A key function of the MPC is helping observers coordinate follow up observations of possible [[near-Earth object]]s (NEOs) via its NEO web form and blog, the [[Near-Earth Object Confirmation Page]].<ref name="MPC-NEO-confirmation" /><ref name="MPC-NEO-blog" /> The MPC is also responsible for identifying, and alerting to, new NEOs with a risk of impacting Earth in the few weeks following their discovery ''(see [[Potentially hazardous object]]s and {{section link||Videos}})''.<ref name="IAU-Centres" />

== History ==

The Minor Planet Center was set up at the [[University of Cincinnati]] in 1947, under the direction of [[Paul Herget]].<ref name="hergetbio" /><ref name="Marsden1980" />{{rp|63}} Upon Herget's retirement on June 30, 1978,<ref name="Marsden1980" />{{rp|67}} the MPC was moved to the Smithsonian Astrophysical Observatory, under the direction of [[Brian G. Marsden]].<ref name="Marsden1980"/>{{rp|67}} From 2006 to 2015,<ref name="MPC-blog-Marsden-stepdown" /> the director of the MPC was [[Timothy Spahr]],<ref name="mpec2010W10" /> who oversaw a staff of five. From 2015 to 2021, the Minor Planet Center was headed by interim director [[Matthew J. Holman|Matthew Holman]].<ref name="MPC-blog-Interim-Director" /> Under his leadership, the MPC experienced a significant period of reorganization and growth, doubling both its staff size and the volume of observations processed per year. Upon Holman's resignation on February 9, 2021 (announced on February 19, 2021) Matthew Payne became acting director of the MPC.<ref name="MPEC-2021-D60" /><ref name="MPC-About" />

=== Directors ===
* 1947–1978: [[Paul Herget]]
* 1978–2006: [[Brian G. Marsden|Brian Marsden]]
* 2006–2015: [[Timothy B. Spahr|Timothy Spahr]]
* 2015–2021: [[Matthew J. Holman|Matthew Holman]]
* 2021–present: Matthew Payne

== {{anchor|Publications}} Periodical publications ==
{{Redirect2|Minor Planet Circulars|Minor Planet Electronic Circulars|the publication by [[Association of Lunar and Planetary Observers|ALPO]]|The Minor Planet Bulletin}}

The MPC periodically releases [[astrometric]] observations of minor planets, as well as of [[comet]]s and [[natural satellite]]s. These publications are the Minor Planet Circulars (MPCs), the Minor Planet Electronic Circulars (MPECs), and the Minor Planet Supplements (MPSs and MPOs).<ref name="MPC-Publications" /> An extensive archive of publications in a PDF format is available at the Minor Planet Center's website. The archive's oldest publication dates back to 1 November 1979 (MPC 4937–5016).<ref name="MPC-Circulars-Archive" /> 
* '''''Minor Planet Circulars''''' ('''''M.P.C.''''' or '''''MPCs'''''), established 1947, is a [[scientific journal]] that is generally published  by the Minor Planet Center on the date of each [[full moon]], when the number of reported observations are minimal due to the brighter night sky. The ''Circulars'' contain astrometric observations, orbits and ephemerides of minor planets, comets and certain natural satellites. The astrometric observations of comets are published in full, while the minor planet observations are summarised by observatory code (the full observations now being given in the ''Minor Planet Circulars'' Supplement). New numberings and namings of minor planets ''(also see [[Naming of Minor Planets]])'', as well as numberings of periodic comets and natural satellites, are announced in the ''Circulars''.  New orbits for comets and natural satellites appear in the ''Circulars''; new orbits for minor planets appear in the Minor Planets and Comets Orbit Supplement ''(see below)''.
* The '''''Minor Planet Electronic Circulars''''' ('''''MPECs''''') are published by the Minor Planet Center. They generally contain [[Astrometry|positional observations]] and [[Kepler orbit|orbits]] of [[unusual minor planet]]s and all [[comet]]s. Monthly lists of observable unusual objects, observable distant objects, observable comets and the [[Critical-list minor planet|critical list of numbered minor planets]] also appear on these circulars. Daily Orbit Update MPECs, issued every day, contain new identifications and orbits of minor planets, obtained over the previous 24 hours.
* The '''''Minor Planets and Comets Supplement''''' ('''''MPS''''') is published on behalf of [[International Astronomical Union|IAU]]'s Division F (Planetary Systems and Bioastronomy)<ref>{{Cite web|url=https://www.iau.org/science/scientific_bodies/divisions/F/|title=Division F Planetary Systems and Astrobiology |publisher=[[International Astronomical Union]] |access-date=2017-11-07}}</ref> by the Minor Planet Center.
* The '''''Minor Planets and Comets Orbit Supplement''''' ('''''MPO''''') is published on behalf of IAU's Division F by the Minor Planet Center.

== Natural Satellites Ephemeris Service ==

The '''Natural Satellites Ephemeris Service''' is an online service of the Minor Planet Center. The service provides "ephemerides, orbital elements and residual blocks for the outer irregular satellites of the giant planets".[https://minorplanetcenter.net//iau/NatSats/NaturalSatellites.html]

== See also ==
* [[Central Bureau for Astronomical Telegrams]]
* [[IAU Circular]]
* [[List of astronomical societies]]
* [[List of minor-planet groups]]
* [[List of minor planets]]
* {{section link|List of minor planets|Main index}}
* [[Meanings of minor-planet names]]

== References ==
{{reflist|30em|refs=

<ref name="IAU-Centres">{{cite book
  |title       = Centres: Minor Planet Center
  |publisher   = [[International Astronomical Union]]
  |url         = https://www.iau.org/science/scientific_bodies/centres/
  |access-date = 20 April 2016 }}</ref>

<ref name="MPC-NEO-confirmation">{{Cite journal
  |title       = The NEO Confirmation Page
  |journal     = [[Planetary and Space Science]]
  |volume      = 46
  |issue       = 2–3
  |page        = 299
  |bibcode     = 1998P&SS...46..299M
  |last1       = Marsden
  |first1      = B. G.
  |authorlink  = Brian G. Marsden
  |last2       = Williams
  |first2      = G. V.
  |date        = February–March 1998
  |doi         = 10.1016/S0032-0633(96)00153-5 }}</ref>

<ref name="MPC-NEO-blog">{{cite web
  |title       = Real time reporting of NEOCP follow up
  |website     = NEOCP Blog
  |publisher   = Minor Planet Center
  |url         = http://minorplanetcenter.net/NEOCPblog/
  |access-date  = 20 April 2016
  |url-status  = dead
  |archive-url = https://web.archive.org/web/20160413020115/http://minorplanetcenter.net/NEOCPblog/
  |archive-date= 2016-04-13 }}</ref>

<ref name="hergetbio">{{cite book
  |chapter     = Paul Herget: 1908–1981
  |author      = Donald E. Osterbrock
  |author2     = P. Kenneth Seidelmann
  |name-list-style=amp
  |title       = Biographical Memoirs of the National Academy of Sciences
  |publisher   = [[National Academies Press]]
  |volume      = 57
  |pages       = 64–65
  |date        = 1987
  |chapter-url = http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/herget-paul.pdf
  |oclc        = 45729798
  |isbn        = 9780585272801 }}</ref>

<ref name="Marsden1980">{{cite journal
  |title       = The Minor Planet Center
  |author      = Brian G. Marsden
  |authorlink  =Brian G. Marsden
  |journal     = [[Celestial Mechanics and Dynamical Astronomy|Celestial Mechanics]]
  |volume      = 22
  |pages       = 63–71
  |date        = July 1980
  |issue = 1
 |bibcode     = 1980CeMec..22...63M
  |doi         = 10.1007/BF01228757 |s2cid = 119526916
 }}</ref>

<ref name="mpec2010W10">{{cite web
  |title       = MPEC 2010-W10: Brian Marsden (1937 Aug. 5{{Snd}} 2010 Nov. 18)
  |work        = Minor Planet Electronic Circular
  |date        = 18 November 2010
  |author      = Gareth V. Williams
  |url         = https://www.minorplanetcenter.net/mpec/K10/K10W10.html }}</ref>

<ref name="MPEC-2021-D60">{{cite web
  |title      = New acting MPC Director – MPEC 2021-D60
  |url        = https://www.minorplanetcenter.net/mpec/K21/K21D60.html
  |work       = Minor Planet Electronic Circular
  |publisher  = Minor Planet Center
  |date       = 19 February 2021
  |access-date= 22 February 2021}}</ref>

<ref name="MPC-blog-Marsden-stepdown">{{cite web
  |title       = Minor Planet Center Director Steps Down
  |work        = The Daily Minor Planet Blog
  |last1       = Galoche
  |first1      = J.L.
  |publisher   = Minor Planet Center
  |url         = http://www.minorplanetcenter.net/blog/?p=911
  |url-status  = dead
  |archive-url = https://web.archive.org/web/20150814031126/http://minorplanetcenter.net/blog/minor-planet-center-director-steps-down/
  |archive-date= 2015-08-14
  |date        = 6 January 2015
  |access-date  = 20 April 2016}}</ref>

<ref name="MPC-blog-Interim-Director">{{cite web
  |title       = Interim Director Appointed to the Minor Planet Center 
  |work        = The Daily Minor Planet Blog
  |last1       = Galoche
  |first1      = J.L.
  |publisher   = Minor Planet Center
  |url         = http://www.minorplanetcenter.org/blog/?p=922
  |url-status  = dead
  |archive-url = https://web.archive.org/web/20150526013828/http://www.minorplanetcenter.org/blog/?p=922
  |archive-date= 2015-05-26
  |date        = 4 February 2015
  |access-date  = 1 December 2015}}</ref>

<ref name="MPC-Publications">{{cite web
  |title       = MPC: Publications
  |publisher   = Minor Planet Center
  |url         = https://minorplanetcenter.net//iau/services/MPCServices.html
  |access-date  = 6 May 2016}}</ref>

<ref name="MPC-Circulars-Archive">{{cite web
  |title       = MPC/MPO/MPS Archive
  |publisher   = Minor Planet Center
  |url         = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
  |access-date  = 6 May 2016}}</ref>

<ref name="MPC-About">{{cite web
  |title       = Staff – Matthew Payne, MPC Acting Director
  |publisher   = Minor Planet Center
  |url         = https://minorplanetcenter.net/about
  |access-date = 22 February 2021}}</ref>

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

== External links ==
* {{Official website|www.minorplanetcenter.net}}
* [https://minorplanetcenter.net//iau/ECS/MPCArchive/MPCArchive_TBL.html MPC/MPO/MPS Archive], all published circulars since 1977 (downloadable as PDF)
* [https://minorplanetcenter.net//iau/MPCORB.html The MPC Orbit (MPCORB) Database]
* [https://web.archive.org/web/20160325123230/http://iawn.net/2015_national_harbor/MPC_IAWN_Holman.pdf The Minor Planet Center Status Report], [[Matthew J. Holman]], ''8 November 2015''
* [https://www.minorplanetcenter.net/mpec/RecentMPECs.html Recent MPECs], list of most-recently published ''Minor Planet Electronic Circulars''

=== Videos ===
* {{YouTube|id=W3nU_6XEsck|title=Asteroid Hazards, Part 1: ''What Makes an Asteroid a Hazard?''}}  {{small|(min. 6:04)}}
* {{YouTube|id=Ar_h-zAccsY|title=Asteroid Hazards, Part 2: ''The Challenge of Detection''}}  {{small|(min. 7:14)}}
* {{YouTube|id=8M_27st1ZCI|title=Asteroid Hazards, Part 3: ''Finding the Path''}}  {{small|(min. 5:38)}}

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