View source for 6P/d'Arrest

{{Short description|Periodic comet}}
{{Use mdy dates|date=April 2012}}
{{Infobox comet
| name            = 6P/d'Arrest
| image           = 6Pd'ArrestZTF.png
| caption         = Comet d'Arrest photographed by the [[Zwicky Transient Facility]] on 21 September 2021
| discoverer      = [[Heinrich Louis d'Arrest]]
| discovery_site  = [[Leipzig]], Germany
| discovery_date  = June 28, 1851
| mpc_name        = {{unbulleted|C/1678 R1, P/1851 M1|P/1857 X1}}
| designations    = {{unbulleted|1910c, 1923b, 1950a|1963f, 1970d, 1976e|1982e, 1987k{{r|ICQ1}}}}
| orbit_ref       = {{r|jpl1|MPC}}
| epoch           = 25 February 2023 ([[Julian day|JD]] 2460000.5)
| observation_arc = 344 years
| earliest_precovery_date = September 11, 1678{{r|Carusi_1991}}
| obs             = 3,732
| perihelion      = 1.353 AU
| aphelion        = 5.639 AU
| semimajor       = 3.497 AU
| period          = 6.539 years
| eccentricity    = 0.61247
| inclination     = 19.511°
| asc_node        = 138.94°
| arg_peri        = 178.09°
| mean            = 79.175°
| tjup            = 2.709
| Earth_moid      = 0.343 AU
| Jupiter_moid    = 0.208 AU
| physical_ref    = {{r|jpl1|Gutiérrez_2003}}
| mean_diameter   = {{cvt|3.2|km|mi}}
| rotation        = {{val|6.67|0.03}} hours
| M1              = 15.9
| M2              = 
| last_p          = September 17, 2021
| next_p          = March 31, 2028{{r|Horizons2028|Kinoshita}}
}}

'''6P/d'Arrest''' (also known as '''d'Arrest's Comet''' or '''Comet d'Arrest''') is a [[List of numbered comets|periodic comet]] orbiting between Mars and Jupiter once every 6.54 years. It is the second of three comets discovered by German astronomer, [[Heinrich Ludwig d'Arrest]].{{efn|In addition to 6P, Heinrich d'Arrest also discovered the comets [[C/1844 Y2]]{{r|jpl2}} and [[C/1857 D1]]{{r|jpl3}}}}

== Observational history ==
It was first observed by Heinrich Ludwig d'Arrest, in Leipzig, Germany, between June 28–30, 1851.{{r|Kronk}} In 1991, a study conducted by [[Andrea Carusi]] and [[Giovanni B. Valsecchi]] (Istituto Astrofisica Spaziale, Rome), alongside [[Ľubor Kresák]] and [[Margita Kresáková]] (Slovak Astronomical Institute, Bratislava) independently suggested that this comet is the same as the comet previously observed by [[Philippe de La Hire]] in 1678.{{r|Carusi_1991|IAUC_5283}}

The comet passed within {{convert|0.151|AU|e6km e6mi|abbr=unit}} from [[Earth]] on August 12, 1976.{{r|jpl1}} Its apparition in 2015 was unfavorable as it had a solar [[Elongation (astronomy)|elongation]] of less than 30 degrees from October 2014 until May 2015.<ref name="MPC-eph"/> The most recent [[perihelion]] passage took place on September 17, 2021, when the comet had a [[solar elongation]] of 95 degrees at approximately [[apparent magnitude]] of 10.{{r|Yoshida}}

== Physical characteristics ==
Guring its 2008 apparition, infrared spectroscopy conducted at the [[Keck Observatory]] has detected emissions of [[water|{{chem|H|2|O}}]], [[methanol|{{chem|CH|3|OH}}]], [[ethane|{{chem|C|2|H|6}}]], [[formaldehyde|{{chem|H|2|CO}}]] and [[ammonia|{{chem|NH|3}}]] from its coma, where the latter three gases were found to be relatively depleted compared to other comets.{{r|Dello_Russo_2009}}

The [[comet nucleus]] is estimated at {{cvt|3.2|km|mi}} in diameter.{{r|jpl1}} Photometric measurements in 1976 revealed a rotation period of around {{val|5.17|0.01}} hours,{{r|Fay_1978}} however this was revised after a periodogram analysis of its lightcurve in 2003 suggests that the comet has a longer rotation period, around {{val|6.67|0.03}} hours.{{r|Gutiérrez_2003}}

== Exploration ==
[[File:6p d'Arrest.jpg|left|thumb|Long-exposure image of Comet d'Arrest taken by [[Elizabeth Roemer]] on 7 May 1970]]

A study in 1966 proposed a [[Mariner program|''Mariner'']]-type mission to 6P/d'Arrest planned to be launched from an [[Atlas-Centaur]] by April 1976, arriving at the comet at a distance of {{cvt|100000|km|mi}} about 115–145 days after launch, however this did not come to fruition.{{r|Kreiter_1966|wired1}}

6P/d was one of a trio of comets alongside [[2P/Encke]] and [[73P/Schwassmann–Wachmann]] targeted by the ill-fated [[CONTOUR]] mission,{{r|Sansovo_2001}} which was launched but lost contact soon after reaching orbit in 2002. Had it been functional, the planned date for CONTOUR's flyby of d'Arrest would have been 2008, after visiting two other comets.{{r|skytel1}}

Around 2007, 6P/d was one of nine comets examined for a preliminary comet [[sample return mission]] study.{{r|Weaver_2007}} By the 2010s, three comet surface sample return missions ([[Comet Nucleus Dust and Organics Return|CONDOR]], [[Comet Rendezvous, Sample Acquisition, Investigation, and Return|CORSAIR]], and [[CAESAR (spacecraft)|CAESAR]]) were selected as finalists for the [[New Frontiers Program]], but the recently studied [[67P/Churyumov–Gerasimenko]] and [[88P/Howell]] were chosen as the selected targets. These proposals were ultimately not selected in favor of the [[Dragonfly (Titan space probe)|''Dragonfly'']] mission to [[Titan (moon)|Titan]].

== See also ==
* [[List of missions to comets]]

== References ==
=== Notes ===
{{Notelist}}

=== Citations ===
{{Reflist|refs=

<ref name="Carusi_1991">{{cite journal
| author1= A. Carusi
| author2= G. B. Valesecchi
| author3= L. Kresak
| author4= M. Kresakova
| title= Observations of Periodic Comet d'Arrest in 1678 and implications for its evolutionary history
| journal= Astronomy & Astrophysics
| year= 1991
| volume= 252
| issue= 1
| pages= 377–384
| bibcode= 1991A&A...252..377C
| s2cid= 118960268
| issn= 0004-6361 }}
</ref>

<ref name="Dello_Russo_2009">{{cite journal
| author1= N. Dello Russo
| author2= R. J. Vervack Jr.
| author3= H. A. Weaver
| author4= H. Kawakita
| author5= H. Kobayashi
| author6= N. Biver
| author7= D. Bockelée-Morvan
| author8= J. Crovisier
| display-authors= 4
| title= The Parent Volatile Composition of 6P/d'Arrest and a Chemical Comparison of Jupiter-Family Comets Measured at Infrared Wavelengths
| journal= The Astrophysical Journal
| year= 2009
| volume= 703
| issue= 1
| pages= 187–197
| bibcode= 2009ApJ...703..187D
| s2cid= 122937365
| doi= 10.1088/0004-637X/703/1/187
| doi-access= free }}
</ref>

<ref name="Fay_1978">{{cite journal
| author1= T. D. Fay Jr.
| author2= W. Wisniewski
| title= The light curve of the nucleus of comet d'Arrest
| journal= Icarus
| year= 1978
| volume= 34
| issue= 1
| pages= 1–9
| s2cid= 124819075
| doi= 10.1016/0019-1035(78)90119-7 }}
</ref>

<ref name="Gutiérrez_2003">{{cite journal
| author1= P. J. Gutiérrez
| author2= J. de León
| author3= L. Jorda
| author4= J. Licandro
| author5= L. M. Lara
| author6= P. Lamy
| display-authors= 3
| title= New spin period determination for comet 6P/d'Arrest
| journal= Astronomy & Astrophysics
| year= 2003
| volume= 407
| issue= 2
| pages= 37–40
| bibcode= 2003A&A...407L..37G
| s2cid= 55635900
| doi= 10.1051/0004-6361:20031066
| doi-access= free }}
</ref>

<ref name="IAUC_5283">{{cite journal
| author1= A. Carusi
| author2= G. B. Valesecchi
| author3= L. Kresak
| author4= M. Kresakova
| author5= G. Sitarski
| editor1= B. G. Marsden
| title= Periodic Comet d'Arrest {{=}} Comet la Hire (1678)
| url= http://www.cbat.eps.harvard.edu/iauc/05200/05283.html
| journal= IAU Circular
| date= 6 June 1990
| volume= 5283
| issue= 1
| bibcode= 1990IAUC.5283....1C }}
</ref>

<ref name="ICQ1">{{cite web
| title= Comet Names and Designations
| url= http://www.icq.eps.harvard.edu/names1.html
| website= International Comet Quarterly
| access-date= 28 June 2025 }}
</ref>

<ref name="jpl1">{{cite web
| title= 6P/d'Arrest – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=6P
| website= ssd.jpl.nasa.gov
| publisher= [[Jet Propulsion Laboratory]]
| access-date= 25 February 2010 }}
</ref>

<ref name="jpl2">{{cite web
| title= C/1844 Y2 (d'Arrest) – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1844Y2
| website= ssd.jpl.nasa.gov
| publisher= [[Jet Propulsion Laboratory]]
| access-date= 28 June 2025 }}
</ref>

<ref name="jpl3">{{cite web
| title= C/1857 D1 (d'Arrest) – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1857D1
| website= ssd.jpl.nasa.gov
| publisher= [[Jet Propulsion Laboratory]]
| access-date= 28 June 2025 }}
</ref>

<ref name="Kreiter_1966">{{cite journal
| author1= T. J. Kreiter
| title= Intercept missions to asteroid Eros in 1974 and comet d'Arrest in 1976
| url= https://ntrs.nasa.gov/api/citations/19660027851/downloads/19660027851.pdf
| journal= NASA Technical Memorandum
| year= 1966
| s2cid= 119055749
| id= NASA TM X-1288 }}
</ref>
 

<ref name="Kronk">{{Cite web
| author1= G. W. Kronk
| title= 6P/d'Arrest
| url= https://cometography.com/pcomets/006p.html
| website= Cometography.com
| access-date= June 7, 2006 }}
</ref>

<ref name="MPC">{{cite web
| title= 6P/d'Arrest Orbit
| url= http://www.minorplanetcenter.net/db_search/show_object?object_id=6P
| publisher= [[Minor Planet Center]]
| access-date= 7 February 2017 }}
</ref>

<ref name="Sansovo_2001">{{cite journal
| author1= G. C. Sanzovo
| author2= A. A. de Almeida
| author3= A. Misra
| author4= R. M. Torres
| author5= D. C. Boice
| author6= W. F. Huebner
| display-authors= 3
| title= Mass-loss rates, dust particle sizes, nuclear active areas and minimum nuclear radii of target comets for missions STARDUST and CONTOUR
| journal= Monthly Notices of the Royal Astronomical Society
| year= 2001
| volume= 326
| issue= 3
| pages= 852–868.
| bibcode= 2001MNRAS.326..852S
| s2cid= 119951312
| doi= 10.1046/j.1365-8711.2001.04443.x
| doi-access= free }}
</ref>

<ref name="skytel1">{{Cite magazine
| author1= D. Tytell
| title= CONTOUR: Missing in Action
| url= https://skyandtelescope.org/astronomy-news/contour-missing-in-action/
| magazine= Sky & Telescope
| date= 23 July 2003
| access-date= 28 December 2017 }}
</ref> 

<ref name="Weaver_2007">{{cite web
| author1= H. A. Weaver
| author2= M. F. A’Hearn
| author3= G. Fountain
| title= Comet Surface Sample Return
| url= https://www.lpi.usra.edu/opag/nov_2007_meeting/presentations/cssr.pdf
| publisher= Lunar and Planetary Institute
| year= 2007
| access-date= 31 December 2017 }}
</ref>

<ref name="wired1">{{cite web
| author1= D. S. F. Portree
| title= Missions to Comet d'Arrest & Asteroid Eros in the 1970s (1966)
| url= https://www.wired.com/2013/04/the-long-wait-for-comets-asteroids-1966/
| website= Wired
| date= 22 April 2013
| access-date= 28 June 2025 }}
</ref>

<ref name="Yoshida">{{cite web
| author1= S. Yoshida
| title= 6P/d'Arrest
| url= http://www.aerith.net/comet/catalog/0006P/index.html
| website= www.aerith.net
| date= 16 March 2014
| access-date= 29 October 2014 }}
</ref>


<ref name="Horizons2028">{{cite web
  |title=Horizons Batch for 6P/d'Arrest (90000144) on 2028-Mar-31
  |publisher=[[JPL Horizons On-Line Ephemeris System|JPL Horizons]]
  |type=Perihelion occurs when rdot flips from negative to positive
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%2790000144%27&START_TIME=%272028-Mar-28%27&STOP_TIME=%272028-Apr-03%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27
  |access-date=2022-06-15}} (JPL#K212/12 Soln.date: 2022-Jun-08)</ref>

<ref name="Kinoshita">{{cite web
  |title=6P/d'Arrest past, present and future orbital elements
  |url=http://jcometobs.web.fc2.com/pcmtn/0006p.htm
  |work=Comet Orbit
  |first=Kazuo |last=Kinoshita
  |date=2016-07-30
  |archive-url=https://web.archive.org/web/20110520031957/http://jcometobs.web.fc2.com/pcmtn/0006p.htm
  |archive-date=2011-05-20
  |url-status=live
  |access-date=2023-07-27}}</ref>

<ref name="MPC-eph">{{cite web
 |title       = Elements and Ephemeris for 6P/d'Arrest
 |publisher   = [[Minor Planet Center]]
 |url         = http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0006P
 |access-date  = 2014-10-29
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20141029154224/http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0006P
 |archive-date = October 29, 2014
 |df          = mdy-all
}} (0006P)</ref>

}}

== External links ==
* {{JPL Small Body|id=1000017}}
* [http://cometbase.net/en/observation/listObserv/479 6P/d'Arrest at CometBase database]
* [https://minorplanetcenter.net/cgi-bin/returnprepeph.cgi?d=c&o=0006P Elements and Ephemeris for 6P/d'Arrest] – [[Minor Planet Center]]
* [http://www.aerith.net/comet/catalog/0006P/index.html 6P/d'Arrest] – Seiichi Yoshida @ aerith.net
* [http://cometography.com/pcomets/006p.html 6P] – [[Gary W. Kronk]]'s Cometography

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[[Category:Periodic comets]]
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