View source for 167P/CINEOS

{{Short description|Periodic comet with 65 year orbit}}
{{Use mdy dates|date=August 2021}}
{{Infobox comet
 | name=167P/CINEOS
 | image=
 | discoverer=[[Campo Imperatore Near-Earth Object Survey|CINEOS]]
 | discovery_date=August 10, 2004
 | designations={{mp|P/2004 PY|42}}
 | epoch=2066-03-11
 | observation_arc = 9.35 years
 | semimajor=16.28 [[Astronomical Unit|AU]]
 | perihelion=11.77 AU<br />(outside [[Saturn]]'s orbit)
 | aphelion=20.8 AU
 | eccentricity=0.27705
 | inclination= 19.0529°
 | max_speed = 9.8 km/s<ref name="Horizons2066"/>
 | min_speed = 5.6 km/s (2033-Nov-30)
 | period=65.67 [[Julian year (astronomy)|yr]]
 | last_p=April 24, 2001<ref name=MPC/>
 | next_p= {{plainlist|
* March 18, 2066<ref name=Horizons2066 />
* March 22, 2066<ref name=MPC/>
* March 23, 2066<ref name="NK1185" />
}}
 | albedo = {{val|0.053|0.019}}
 | spectral_type  = sdfg
 | dimensions     = {{val|66.17|22.9|ul=km}}<ref name=jpldata/>
 | tjup           = 3.52
}}

'''167P/CINEOS''' ({{mp|P/2004 PY|42}}) is a large [[List of periodic comets|periodic]] [[comet]] and active, grey [[Centaur (small Solar System body)|centaur]], approximately {{convert|66|km|mi|abbr=off|sigfig=2|sp=us}} in diameter, orbiting the Sun outside the orbit of [[Saturn]]. It was discovered on August 10, 2004, by astronomers with the [[Campo Imperatore Near-Earth Object Survey|CINEOS survey]] at [[Gran Sasso]] in Italy. It is one of only a handful known [[Chiron-type comet]]s.

The [[comet nucleus]] (~66&nbsp;km) is roughly half the size of {{mpl|C/2014 UN|271}} (Bernardinelli–Bernstein) and it has a similar [[perihelion]] point just outside the orbit of [[Saturn]].

{| class="wikitable sortable" style="font-size: 0.9em;"
|+Large comets with perihelion near Saturn's orbit at 10 AU
! Comet
! [[Comet nucleus|Nucleus]]<br/>diameter
! [[Perihelion]]<br/>(Sun approach)
! Perihelion<br/>velocity
|-
|[[95P/Chiron]] || 215&nbsp;km || 8.5 AU || 12.0&nbsp;km/s
|-
|[[C/2014 UN271 (Bernardinelli–Bernstein)]] || 120&nbsp;km || 10.95 AU || 12.7&nbsp;km/s
|-
|'''167P/CINEOS''' || 66&nbsp;km || 11.77 AU || 9.8&nbsp;km/s<ref name="Horizons2066"/>
|}

== Description ==

Due to its high [[Tisserand's parameter|Jupiter tisserand]] of 3.5, and a [[semi-major axis]] larger than that of [[Jupiter]], 167P/CINEOS is classified as a [[Chiron-type comet]], named after the groups namesake, [[2060 Chiron]] or 95P/Chiron, designated as both [[minor planet]] and comet.<ref name=jpldata/>

167P/CINEOS was first reported as a minor planet, designated {{mp|2004 PY|42}}, but was found to have a very faint asymmetric [[Coma (cometary)|cometary coma]].<ref name="Romanishin-2005" /> Contrary to Chiron, which is the prototype object for the dynamical group of centaurs, 167P/CINEOS has no "dual status" as comet ''and'' minor planet, and demonstrates the inconsistencies in applying the current rules for designating [[small Solar System bodies]].<ref name="Green-2005" /> 167P/CINEOS not only has [[orbital parameters]] similar to those of Chiron, but also a low [[Distant object color indices|B–R magnitude]] of {{val|1.29|0.03}}, which places it into the group grey centaurs.<ref name="Tegler-2016" />

In June 2039, 167P/CINEOS will pass 1.64&nbsp;[[Astronomical Unit|AU]] from [[Uranus]].<ref name=jpldata/>

== References ==
{{reflist|refs=

<ref name=jpldata>{{cite web
  |type=2011-10-19 last obs (arc=9.35 years)
  |title=JPL Small-Body Database Browser: 167P/CINEOS
  |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=167P&view=OPC
  |access-date=2012-07-12}}</ref>

<ref name=MPC>{{cite web
  |title=167P/CINEOS Orbit
  |url=http://www.minorplanetcenter.net/db_search/show_object?object_id=167P
  |publisher=[[Minor Planet Center]]
  |access-date=2014-06-18}}</ref>

<ref name="Horizons2066">{{cite web
  |title=Horizons Batch for 167P/CINEOS on 2066-Mar-18
  |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=%27167P%27&START_TIME=%272066-Mar-17%27&STOP_TIME=%272066-Mar-21%27&STEP_SIZE=%271%20hours%27&QUANTITIES=%2719,22%27
  |archive-url=https://web.archive.org/web/20220624114237/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27167P%27&START_TIME=%272066-Mar-17%27&STOP_TIME=%272066-Mar-21%27&STEP_SIZE=%271%20hours%27&QUANTITIES=%2719%27
  |archive-date=2022-06-24
  |url-status=live
  |accessdate=2022-06-24}} (JPL#22 Soln.date: 2021-Apr-15)</ref>

<ref name="NK1185">{{cite web
  |date=2005-06-18
  |title=167P/CINEOS (2004 PY42) (NK 1185)
  |publisher=OAA Computing and Minor Planet Sections
  |author=Syuichi Nakano
  |author-link=Syuichi Nakano
  |url=http://www.oaa.gr.jp/~oaacs/nk/nk1185.htm
  |access-date=2012-02-20}}</ref>

<ref name="Romanishin-2005">{{cite journal
  |last1      = Romanishin |first1 = W.
  |last2      = Tegler |first2 = S. C.
  |last3      = Boattini |first3 = A.
  |last4      = de Luise |first4 = F.
  |last5      = di Paola |first5 = A.
  |date       = June 2005
  |title      = Comet C/2004 PY_42 (cineos)
  |journal    = International Astronomical Union Circular – Central Bureau for Astronomical Telegrams
  |volume     = 8545
  |page       = 1
  |url        = http://www.cbat.eps.harvard.edu/iauc/08500/08545.html
  |bibcode    = 2005IAUC.8545....1R
  |issn       = 0081-0304}}</ref>

<ref name="Green-2005">{{cite journal
  |last1      = Green |first1 = D. W. E.
  |date       = June 2005
  |title      = Comets 165P/2000 B4, 166P/2001 T4, and 167P/2004 PY_42
  |journal    = International Astronomical Union Circular – Central Bureau for Astronomical Telegrams
  |volume     = 8552
  |page       = 2
  |url        = http://www.cbat.eps.harvard.edu/iauc/08500/08552.html
  |bibcode    = 2005IAUC.8552....2G
  |issn       = 0081-0304}}</ref>

<ref name="Tegler-2016">{{cite journal
  |last1      = Tegler |first1 = S. C.
  |last2      = Romanishin |first2 = W.
  |last3      = Consolmagno |first3 = G. J.
  |last4      = J. |first4 = S.
  |date       = December 2016
  |title      = Two Color Populations of Kuiper Belt and Centaur Objects and the Smaller Orbital Inclinations of Red Centaur Objects
  |journal    = The Astronomical Journal
  |volume     = 152
  |issue      = 6
  |page       = 210
  |bibcode    = 2016AJ....152..210T
  |issn       = 0004-6256
  |doi        = 10.3847/0004-6256/152/6/210|doi-access= free
  }}</ref>

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

== External links ==
* [http://www.aerith.net/comet/catalog/0167P/2004PY42.html 167P on Seiichi Yoshida's comet list]
* {{JPL small body|title=167P/CINEOS|id=1001647}}

{{PeriodicComets Navigator|166P/NEAT|168P/Hergenrother}}
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{{DEFAULTSORT:Cineos, 167P}}
[[Category:Chiron-type comets]]
[[Category:Periodic comets]]
[[Category:Numbered comets|0167]]
[[Category:Centaurs (small Solar System bodies)|*]]
[[Category:Discoveries by CINEOS|*]]
[[Category:Astronomical objects discovered in 2004|20040810]]