View source for (523764) 2014 WC510

{{short description|Binary trans-Neptunian object}}
{{DISPLAYTITLE:{{mp|(523764) 2014 WC|510}}}}
{{dmy|date=September 2020}}
{{Infobox planet
 | minorplanet     = yes
 | name            = {{mp|(523764) 2014 WC|510}}
 | background      = #C2E0FF
 | image           = 2014 WC510 Hubble 10x upscale.png
 | image_scale     = 
 | caption         = {{mp|2014 WC|510}} imaged by the [[Hubble Space Telescope]] in March 2024
 | discovery_ref   = <ref name="MPC-object" />
 | discoverer      = [[Pan-STARRS|Pan-STARRS 1]]
 | discovery_site  = [[Haleakalā Observatory|Haleakalā Obs.]]
 | discovered      = 8 September 2011<br/>{{small|(first imaged)}}
 | earliest_precovery_date = 
 | mpc_name        = {{mp|2014 WC|510}}
 | alt_names       = 
 | pronounced      = 
 | named_after     = 
 | mp_category     = [[plutino]]<ref name="Buie" />{{·}}[[Trans-Neptunian object|TNO]]<ref name="jpldata" /><br/>[[Distant minor planet|distant]]<ref name="MPC-object" />{{·}}[[minor-planet moon|binary]]<ref name="Leiva2020" />
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 31 May 2020 ([[Julian day|JD]] 2459000.5)
 | uncertainty     = 2
 | observation_arc = 7.49 [[Julian year (astronomy)|yr]] (2,737 days)
 | aphelion        = 48.936 [[astronomical unit|AU]]
 | perihelion      = 29.535
 | semimajor       = 39.236
 | eccentricity    = 0.24724
 | period          = 245.77 yr
 | mean_anomaly    = 342.994[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.0040103195|sup=ms}} / day
 | inclination     = 19.542°
 | asc_node        = 194.464°
 | arg_peri        = 289.173°
 | satellites      = 1
 | mean_diameter   = {{val|181|16|ul=km}} {{small|(primary)}}<ref name="Leiva2020" /><br/>{{val|138|32|u=km}} {{small|(secondary)}}<ref name="Leiva2020" />
 | rotation        = 
 | albedo          = {{val|0.051|0.017}}<ref name="Leiva2020" />
 | spectral_type   = 
 | magnitude       = 22.0<ref name="MPC-object" />
 | abs_magnitude   = {{val|7.2|0.3}}<ref name="Leiva2020" />
}}

'''{{mp|(523764) 2014 WC|510}}''' ([[provisional designation]] '''{{mp|2014 WC|510}}''') is a [[binary system|binary]] [[trans-Neptunian object]] and [[plutino]] discovered on 8 September 2011 by the [[Pan-STARRS]] survey at the [[Haleakalā Observatory]] in [[Hawaii]]. It orbits in the [[Kuiper belt]], a region of icy objects orbiting beyond [[Neptune]] in the outer [[Solar System]]. Astronomers discovered the binary nature of {{mp|2014 WC|510}} when its two components [[stellar occultation|occulted]] a star on 1 December 2018. The components of the {{mp|2014 WC|510}} binary system, which have diameters of {{cvt|180|km|mi}} and {{cvt|140|km|mi}}, orbit each other at a separation distance of roughly {{cvt|2600|km|mi}}.

== Observations ==
=== Discovery ===
The [[Pan-STARRS]] survey is conducted by one of the two 1.8-meter [[Ritchey–Chrétien telescope]]s (named Pan-STARRS 1 and 2) at the [[Haleakalā Observatory]] atop the [[Hawaii|Hawaiian]] island of [[Maui]]. {{mp|2014 WC|510}} was first observed by Pan-STARRS 1 on 8 September 2011,<ref name="MPC-object"/> but was not recognized as a new object until 20 November 2014.<ref name="MPEC-2016-O238"/> After Pan-STARRS 1 made further observations of the object, the [[Minor Planet Center]] announced {{mp|2014 WC|510}} as a newly-discovered [[minor planet]] on 17 July 2016.<ref name="MPEC-2016-O238"/> The minor planet [[provisional designation]] given to the object, {{mp|2014 WC|510}}, does not necessarily reflect its discovery date but is rather derived from the date of observation on which the object was first recognized.<ref name="HowNamed"/> The observers operating the Pan-STARRS 1 telescope in these observations were B. Gibson, T. Goggia, N. Primak, A. Schultz, and M. Willman.<ref name="MPEC-2016-O238"/> After {{mp|2014 WC|510}} was observed long enough to secure its orbit, the Minor Planet Center gave it the permanent [[Minor planet designation|minor planet number]] {{LoMP|523764|523764}} on 25 September 2018 and declared the object's official discovery date as 8 September 2011,<ref name="MPC111781"/> in accordance with the Minor Planet Center's discovery rules.<ref name="HowNamed"/>

=== Occultation ===
[[File:2014 WC510 occultation chords preferred - Leiva et al. 2020 Fig 6.jpg|thumb|left|upright=1.5|Plot of [[chord (astronomy)|chords]] obtained from the 1 December 2018 [[occultation (astronomy)|occultation]]. Because the occulted star is a [[double star]], the components of {{mp|2014 WC|510}} were detected twice (each detection represented by green and blue).]]
On 1 December 2018, {{mp|2014 WC|510}} [[occultation|occulted]] a 15th-[[apparent magnitude|magnitude]] [[double star]], blocking out its starlight for a maximum duration of approximately 11 seconds. The stellar occultation was observed by astronomers and citizen scientists across the [[West Coast of the United States|West Coast]] of the United States and Canada. Of the 41 participating sites, six of them reported dimming in the star's brightness, signifying likely positive detections of the occultation. Five of these sites reported two consecutive dimmings due to the occulted star's double nature; {{mp|2014 WC|510}} occulted one of the two stars being observed.<ref name="Leiva2020" /> These observations were part of a campaign coordinated by the Research and Education Collaborative Occultation Network (RECON), a [[citizen science]] project dedicated to observing occultations by trans-Neptunian objects.<ref name="Gough2020" /><ref name="SwRI" />

Prior to the occultation, {{mp|2014 WC|510}} had only been observed by Pan-STARRS over an [[observation arc]] of 3 years. The calculated orbit from these Pan-STARRS observations had significant [[uncertainty parameter|uncertainty]], which would have been unreliable for predicting occultations.<ref name="MPEC-2016-O238" /> In an effort to reduce the orbital uncertainty, the RECON project collaborated with the Pan-STARRS project to do a [[precovery]] search of archival Pan-STARRS images to gather extensive [[astrometry|astrometric]] positions of {{mp|2014 WC|510}}.<ref name="Leiva2020" /> Follow-up observations by Pan-STARRS were also conducted through 2016–2018 and helped extend {{mp|2014 WC|510}}'s observation arc to 6.3 years.<ref name="MPC-object" /> Although an observation arc of this length is generally unreliable for predicting occultations especially by distant objects, this was compensated by Pan-STARRS's highly accurate astrometry, allowing for {{mp|2014 WC|510}}'s orbital uncertainty to be significantly reduced.<ref name="Leiva2020" />

== Orbit and classification ==
{{mp|2014 WC|510}} is classified as a [[plutino]], a subgroup of the [[resonant trans-Neptunian object]]s located in the inner region of [[Kuiper belt]]. Named after the group's largest member, [[Pluto]], the plutinos are in a 2:3 [[Orbital resonance#Plutino resonances|mean-motion orbital resonance]] with [[Neptune]]. That is, they complete two orbits around the Sun for every three orbits that Neptune takes.<ref name="Buie" /> {{mp|2014 WC|510}} orbits the Sun at an average distance of {{convert|39.24|AU|km mi|sigfig=3|lk=in}}, taking 245.8 years to complete a full orbit.<ref name="jpldata" /> This is characteristic of all plutinos, which have orbital periods around 250 years and [[semi-major axes]] around 39&nbsp;AU.<ref name="johnston-list" />

Like Pluto, {{mp|2014 WC|510}}'s orbit is elongated and inclined to the [[ecliptic]].<ref name="johnston-list" /> {{mp|2014 WC|510}} has an [[orbital eccentricity]] of 0.25 and an [[orbital inclination]] of 19.5 [[degree (angle)|degree]]s with respect to the [[ecliptic]]. Over the course of its orbit, {{mp|2014 WC|510}}'s distance from the Sun varies from 29.5&nbsp;AU at [[perihelion]] (closest distance) to 48.9&nbsp;AU at [[aphelion]] (farthest distance).<ref name="jpldata" /> {{mp|2014 WC|510}} has last passed aphelion in the early 20th century, and is now moving closer to the Sun, approaching perihelion by 2032.<ref name="jpldata" /><ref name="Horizons" /> Simulations by the [[Deep Ecliptic Survey]] show that {{mp|2014 WC|510}} can acquire a perihelion distance (''q<sub>min</sub>'') as small as 28.7&nbsp;AU over the next 10&nbsp;million years.<ref name="Buie" />

== Binary system ==
Observations of the December 2018 occultation revealed that {{mp|2014 WC|510}} is a [[binary system]] consisting of two components at a relatively close separation from each other. Of the six sites that reported positive detections of the occultation, one site located in [[Bishop, California]], detected a shorter dimming event separate from the main detections by the other five sites located south of it. A 2020 study led by Rodrigo Leiva, [[Marc Buie]], and collaborators analyzed the occultation data and determined that the detection from Bishop was most likely an occultation by a [[minor-planet moon|secondary component]] of {{mp|2014 WC|510}}.<ref name="Leiva2020" /><ref name="SwRI" />

Since the two components were only observed for a short period of time during the occultation, the binary system's [[orbital parameters]] have not been determined. The projected separation distance between the primary and secondary during the occultation was {{cvt|349 ± 29|km|mi}}, derived from an [[angular separation]] of {{val|16|1}} [[arcsecond|milliarcsecond]]s (mas).<ref name="Leiva2020" /> This small projected separation distance initially led researchers to believe that {{mp|2014 WC|510}} is a compact binary system,<ref name="Leiva2020"/> but high-resolution imaging by the [[Hubble Space Telescope]] on 6 March 2024 revealed that {{mp|2014 WC|510}}'s components are more widely separated from each other by at least {{cvt|2600|km|mi}} (angular separation 120 mas).<ref name="CBET5413"/>{{efn|The projected separation ''d'' {{=}} {{val|2600|u=km}} is calculated from the [[tangent (trigonometry)|tangent]] of the components' angular separation of ''θ'' {{=}} {{val|3.33|e=-5}} [[degree (angle)|degrees]] (120 [[milliarcsecond|mas]]): <math>\tan \theta = \frac \mathrm{d}\mathrm{r}</math>, where the ''r'' is the radial distance between Earth and {{mp|2014 WC|510}} in km.<ref name="HST17524"/>}} The large change in projected separation distance between the occultation and Hubble observations suggests that the {{mp|2014 WC|510}} system was in or near an edge-on configuration, in which the components of the {{mp|2014 WC|510}} system may have transited or occulted each other from Earth.<ref name="CBET5413"/>

Most models of the [[formation of the Solar System]] indicate that most TNOs have formed as binaries, hence they are expected to be common especially in the [[Kuiper belt]] population.<ref name="SwRI" /> While most known binary TNOs appear to have wide mutual orbits, tight binary TNOs are thought to have a higher chance of survival after their formation. {{mp|2014 WC|510}} belongs to the population of smaller TNOs, which are expected to have a primordial origin similar to the [[classical Kuiper belt object]] [[486958 Arrokoth]].<ref name="Leiva2020" />

== Physical characteristics ==
Assuming a circular projected shape for the components' occultation profiles, the diameters of the primary and secondary are estimated to be {{cvt|181 ± 16|km|mi}} and {{cvt|138 ± 32|km|mi}}, respectively.<ref name="Leiva2020" /> The diameter ratio of the secondary to the primary is 0.76:1.00—the secondary component is approximately 75% as large as the primary.<ref name="johnston"/> Hubble observations from 2024 show that the secondary component is about 25–30% fainter than the primary.<ref name="CBET5413"/> The orbital distance and period of the components is unknown, so the mass and density of the {{mp|2014 WC|510}} system cannot be derived. The individual components of the {{mp|2014 WC|510}} system are among the smallest trans-Neptunian objects with sizes measured with stellar occultations, following the Kuiper belt object 486958 Arrokoth (~{{val|30|u=km}}).<ref name="Leiva2020" />

Given the components' estimated diameters and their combined [[absolute magnitude]] of 7.2, their calculated [[geometric albedo]]s indicate that they have dark surfaces, reflecting about 5% of incident visible light. However, the estimated geometric albedo may be subject to a systematic error depending on the true shapes and [[photometry (astronomy)|photometric]] properties of the components, resulting in a significant uncertainty of ±2%. Nonetheless, {{mp|2014 WC|510}} is one of the darkest objects measured with stellar occultations, being darker than 486958 Arrokoth.<ref name="Leiva2020" />

== Notes ==
{{notelist}}

== References ==
{{reflist|refs=

<ref name="jpldata">{{Cite web |title=JPL Small-Body Database Browser: 523764 (2014 WC510) |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2523764 |access-date= 2020-09-28 |publisher=[[Jet Propulsion Laboratory]] |type=2019-03-07 last obs.}}</ref>

<ref name="MPC-object">{{Cite web |title=(523764) = 2014 WC510 |url=http://www.minorplanetcenter.net/db_search/show_object?object_id=523764 |access-date= 2020-09-28  |website=Minor Planet Center |publisher=International Astronomical Union}}</ref>

<ref name="Buie">{{Cite web |last=Buie |first=M. W. |authorlink=Marc W. Buie |title=Orbit Fit and Astrometric record for 523764 |url=http://www.boulder.swri.edu/~buie/kbo/astrom/523764.html |access-date= 2020-09-28  |publisher=Southwest Research Institute}}</ref>

<ref name="Horizons">{{cite web |title=HORIZONS Web-Interface |type=Settings: Sun (body center) [500@10]; Start=1900-01-01, Stop=2032-02-01, Step=30 d |url=https://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=523764 |publisher=Jet Propulsion Laboratory |accessdate= 2020-09-30}}</ref>

<ref name="HowNamed">{{Cite web |title=How Are Minor Planets Named? |url=https://www.minorplanetcenter.net/iau/info/HowNamed.html |access-date= 2020-09-30  |website=Minor Planet Center |publisher=International Astronomical Union}}</ref>

<ref name="johnston-list">{{Cite web |last=Johnston |first=W. R. |title=List of Known Trans-Neptunian Objects |url=http://www.johnstonsarchive.net/astro/tnoslist.html |work=Johnston's Archive |date= 2020-08-18 |access-date= 2020-09-30}}</ref>

<ref name="MPEC-2016-O238">{{Cite journal |date= 2016-07-25 |title=MPEC 2016-O238: 2014 WC510 |url=https://minorplanetcenter.net/mpec/K16/K16ON8.html |publisher=Minor Planet Center |bibcode=2016MPEC....O..238G |journal=Minor Planet Electronic Circular|last1=Gibson |first1=B. |last2=Goggia |first2=T. |last3=Primak |first3=N. |last4=Schultz |first4=A. |last5=Willman |first5=M. |last6=Chambers |first6=K. |last7=Chastel |first7=S. |last8=Chen |first8=Y. -T. |last9=Denneau |first9=L. |last10=Flewelling |first10=H. |last11=Holman |first11=M. |last12=Huber |first12=M. |last13=Jedicke |first13=R. |last14=Lackner |first14=M. |last15=Lilly |first15=E. |last16=Lin |first16=H. -W. |last17=Magnier |first17=E. |last18=Micheli |first18=M. |last19=Payne |first19=M. |last20=Veres |first20=P. |last21=Wainscoat |first21=R. |last22=Waters |first22=C. |last23=Weryk |first23=R. |volume=2016-O238 }}</ref>

<ref name="MPC111781">{{Cite web |date= 2018-09-25 |title=M.P.C. 111781 |url=https://minorplanetcenter.net/iau/ECS/MPCArchive/2018/MPC_20180925.pdf |access-date= 2020-09-28  |website=Minor Planet Circular |publisher=Minor Planet Center}}</ref>

<ref name="Leiva2020">{{Cite journal |last1=Leiva |first1=Rodrigo |last2=Buie |first2=Marc W. |last3=Keller |first3=John M. |last4=Wasserman |first4=Lawrence H. |last5=Kavelaars |first5=J. J. |last6=Bridges |first6=Terry |display-authors=etal |date=September 2020 |title=Stellar Occultation by the Resonant Trans-Neptunian Object (523764) 2014 WC510 Reveals a Close Binary TNO |journal=The Planetary Science Journal |volume=1 |issue=2 |pages=48 |doi=10.3847/PSJ/abb23d|doi-access=free |bibcode=2020PSJ.....1...48L|url=https://hal.archives-ouvertes.fr/hal-03256653/file/Leiva_2020_Planet._Sci._J._1_48.pdf }}</ref>

<ref name="SwRI">{{cite web |title=SwRI study describes discovery of close binary trans-Neptunian object |url=https://www.swri.org/press-release/recon-close-binary-trans-neptunian-object |date= 2020-09-28 |access-date= 2020-09-28  |publisher=Southwest Research Institute}}</ref>

<ref name="Gough2020">{{cite web |last=Gough |first=Evan |title=Astronomers Find a New Binary Object in the Kuiper Belt |url=https://www.universetoday.com/148082/astronomers-find-a-new-binary-object-in-the-kuiper-belt/ |date= 2020-09-29 |access-date= 2020-09-29  |work=Universe Today}}</ref>

<ref name="johnston">{{cite web |last=Johnston |first=Wm. Robert |title=(523764) 2014 WC510 |url=http://www.johnstonsarchive.net/astro/astmoons/am-523764.html |date= 2020-10-11 |access-date= 2020-10-11  |work=Asteroids with Satellites Database|publisher=Johnston's Archive}}</ref>

<!-- not used
<ref name="Stern-MOP">{{cite web |title=New Horizons Kuiper Extended Mission Science Overview |url=https://lasp.colorado.edu/home/mop/files/2021/06/Stern.pdf |first=Alan |last=Stern |work=Laboratory for Atmospheric and Space Physics |publisher=University of Colorado Boulder |date=2021-06-21 |accessdate=2021-11-13}}</ref> -->

<ref name="CBET5413">{{cite web
  |title      = CBET 5413: (523764) 2014 WC_510
  |url        = http://www.cbat.eps.harvard.edu/iau/cbet/005400/CBET005413.txt
  |first = Daniel W. E. |last = Green
  |work       = Central Bureau Electronic Telegram
  |publisher  = Central Bureau for Astronomical Telegrams
  |date       = 2024-07-15
  |accessdate = 2024-09-06}}</ref>

<ref name="HST17524">{{cite journal
  |title      = A Deep Search for Moons around Contact Binary Trans-Neptunian Objects
  |url        = https://archive.stsci.edu/proposal_search.php?id=17524&mission=hst
  |first1 = Audrey |last1 = Thirouin
  |first2 = Keith S. |last2 = Noll
  |first3 = Scott S. |last3 = Sheppard
  |journal    = Mikulski Archive for Space Telescopes
  |publisher  = Space Telescope Science Institute
  |date       = August 2023
  |page       = 17524
  |id         = Cycle 32
  |bibcode    = 2023hst..prop17524T}}</ref>

}}

== External links ==
* [https://www.swri.org/press-release/recon-close-binary-trans-neptunian-object SwRI study describes discovery of close binary trans-Neptunian object], 28 September 2020, [[Southwest Research Institute]]
* [https://meetingorganizer.copernicus.org/EPSC-DPS2019/EPSC-DPS2019-964-1.pdf A stellar occultation by a small plutino with RECON], Rodrigo Leiva et al., September 2019, Europlanet Science Congress–[[Division for Planetary Sciences]] Joint Meeting 2019
* [http://www.minorplanet.info/BinAst5/Uploads/Buie_Abstract.pdf Tight and contact TNO binaries with stellar occultations]{{Dead link|date=June 2023 |bot=InternetArchiveBot |fix-attempted=yes }}, [[Marc W. Buie]] et al., 2019
* [http://www.johnstonsarchive.net/astro/astmoons/am-523764.html (523764) 2014 WC510], Wm. Robert Johnston, Asteroids with Satellites Database—Johnston's Archive, 11 October 2020
* {{JPL small body|id=523764}}

{{Minor planets navigator |(523759) 2014 WK509 |number=523764 |PageName={{mp|(523764) 2014 WC|510}} |(523775) 2014 YB35 }}
{{Trans-Neptunian objects}}
{{Small Solar System bodies}}

{{DEFAULTSORT:523764}}
[[Category:Plutinos]]
[[Category:Minor planet object articles (numbered)]]
[[Category:Binary trans-Neptunian objects]]
[[Category:Discoveries by Pan-STARRS]]
[[Category:Objects observed by stellar occultation]]
[[Category:Astronomical objects discovered in 2011|20110908]]