View source for Nix (moon)

{{Infobox planet
| name = Nix
| image = Nix best view-true color.jpg
| caption = The highest-resolution image of Nix, taken by ''[[New Horizons]]'' on 14&nbsp;July 2015. Image captured in grayscale by [[LORRI]], color added based on other images from [[New Horizons#Ralph telescope|Ralph MVIC]].

| discoverer = [[Hubble Space Telescope]]<br>Pluto Companion Search Team
| discovered = 15 June 2005
| alt_names = ({{val|134340}}) Pluto II<ref name="Nomenclature">{{cite web
 |date=2009-11-09
 |title=Gazetteer of Planetary Nomenclature
 |publisher=IAU Working Group for Planetary System Nomenclature (WGPSN)
 |author=Jennifer Blue
 |url=http://planetarynames.wr.usgs.gov/append7.html#DwarfPlanets
 |accessdate=2010-08-30}}</ref>
 | named_after = [[Nyx (mythology)|Nyx]]
 | pronounced = {{IPAc-en|ˈ|n|ɪ|k|s}}
 | note = yes
 | adjectives = Nictian
 | orbit_ref = <ref name="ShowalterHamilton2015">{{cite journal|last1=Showalter|first1=M. R.|author1link=Mark R. Showalter|last2=Hamilton|first2=D. P.|title=Resonant interactions and chaotic rotation of Pluto's small moons|journal=Nature|volume=522|issue=7554|date=3 June 2015|pages=45–49|doi=10.1038/nature14469|pmid=26040889|bibcode=2015Natur.522...45S|s2cid=205243819}}</ref>
 | semimajor = {{val|48694|3|u=km}}
 | eccentricity = {{val|0.00000|}}<ref name="scimag000">{{cite journal|last1=Stern|first1=S. A.|last2=Bagenal|first2=F.|last3=Ennico|first3=K.|last4=Gladstone|first4=G. R.|title=The Pluto system: Initial results from its exploration by New Horizons|journal=Science|date=15 October 2015|volume=350|issue=6258|pages=aad1815|doi=10.1126/science.aad1815|pmid=26472913|display-authors=etal|arxiv = 1510.07704 |bibcode = 2015Sci...350.1815S |s2cid=1220226}}</ref>
 | period = {{val|24.85463|0.00003|u=d}}
 | inclination = {{val|0.133|0.008|u=°}}
 | satellite_of = [[Pluto]]
 
 | dimensions =  ≈ {{val|50|x|35|x|33|u=km}}<ref name=LPSC>{{cite web|url=http://livestream.com/viewnow/LPSC2016|title=2016 Lunar & Planetary Science Conference by National Institute of Aerospace|publisher=|access-date=2018-02-16|archive-date=2018-06-23|archive-url=https://web.archive.org/web/20180623004727/https://livestream.com/viewnow/LPSC2016|url-status=dead}}</ref>
| mean_radius        =
| mass = {{val|4.5|4.0|e=16|u=kg}}<ref name="scimag000"/>
| density =
| single_temperature = 33–55 [[Kelvin|K]]
| rotation = 1.829 ± 0.009 d<ref name=LPSC/><br>
chaotic<ref>{{cite web|url=http://www.nasa.gov/press-release/nasa-s-hubble-finds-pluto-s-moons-tumbling-in-absolute-chaos|title=NASA's Hubble Finds Pluto's Moons Tumbling in Absolute Chaos|first=Karen|last=Northon|date=3 June 2015|publisher=}}</ref> (increased by 10% between discovery and flyby)<ref name=Lakdawalla1110>{{cite web|url=http://www.planetary.org/blogs/emily-lakdawalla/2015/dps15-1110-small-moons.html|title=DPS 2015: Pluto's small moons Styx, Nix, Kerberos, and Hydra [UPDATED]|website=www.planetary.org}}</ref>
| axial_tilt = 132°<ref name=Lakdawalla1110/> (to orbital plane; July 2015)
| albedo = 0.56 ± 0.05 geometric<ref name=LPSC/>
| magnitude = 23.38–23.7 (measured)<ref name="Stern06b" />
}}

[[Image:Pluto system 2005 discovery images.jpg|thumb|250px|right|Discovery images of ''' Nix and Hydra''']]

'''Nix''' is a non-[[Sphere|spherical]] [[Satellite (natural)|moon]] of [[Pluto]]. It was found along with [[Hydra (moon)|Hydra]] in June 2005 by the [[Hubble Space Telescope]] Pluto Companion Search Team.

The discovery images were taken on May 15, 2005 and May 18, 2005; the moons were independently found by Max J. Mutchler on June 15, 2005 and Andrew J. Steffl on August 15, 2005. The discoveries were announced on October 31, 2005, after confirmation from photographs archived in 2002. The moon were designated '''S/2005 P 1''' (Hydra) and '''S/2005 P 2''' (Nix).<ref name="IAUC8625">[http://cfa-www.harvard.edu/iau/special/08625.pdf IAU Circular No. 8625] describing the discovery</ref><ref name="IAUC8723"/>

The moon follows a circular orbit in the same plane as [[Charon (moon)|Charon]]. It takes 24.9 days to circle around Pluto.

Before its size was directly measured, the moon was calculated to have a diameter of between 46&nbsp;km, if its [[albedo|reflectivity]] is similar to Charon's 35%, and 137&nbsp;km, if it had a reflectivity of 4%, like the darkest [[Kuiper belt]] objects.<ref name="Weaver2006">{{cite journal | author = H. A. Weaver |display-authors = 4 |author2 = S. A. Stern |author3 = M. J. Mutchler |author4 = A. J. Steffl|author5 = M. W. Buie |author6 = W. J. Merline|author7 = J. R. Spencer |author8 = E. F. Young |author9 = L. A. Young |name-list-style = amp |date=23 February 2006 | title = Discovery of two new satellites of Pluto | url = https://archive.org/details/sim_nature-uk_2006-02-23_439_7079/page/943 | journal = Nature | volume = 439| issue = 7079 | pages = 943–945| doi = 10.1038/nature04547 | arxiv = astro-ph/0601018 | pmid = 16495991|bibcode = 2006Natur.439..943W |s2cid = 1456215 }}</ref>  Nix is slightly fainter than [[Hydra (moon)|Hydra]], suggesting that it is somewhat smaller in size.<ref name="Stern06b"/>  In the discovery image, Nix is 6,300 times fainter than Pluto.<ref name=brightness>Brightness Difference on 2005-05-15: (5th root of 100) ^ (Nix [[Apparent Magnitude|APmag]] 23.38 - Pluto APmag 13.87) = 6,368x</ref>

Early research appeared to show that Nix was reddish like [[Pluto]] and unlike the other moons,<ref name="Buie06">{{Cite journal|title= Orbits and Photometry of Pluto's Satellites: Charon, S/2005 P1, and S/2005 P2|url=https://archive.org/details/sim_astronomical-journal_2006-07_132_1/page/290 |journal=Astronomical Journal |year=2006 |volume=132 |pages=290–298 |doi=10.1086/504422 |arxiv=astro-ph/0512491 |s2cid=119386667 |last1=Buie |first1=Marc W. |last2=Grundy |first2=William M. |last3=Young |first3=Eliot F. |last4=Young |first4=Leslie A. |last5=Stern |first5=S. Alan |issue=1 |bibcode=2006AJ....132..290B }}([http://arxiv.org/abs/astro-ph/0512491v2 Final preprint])  ''a, i, e'' per [http://ssd.jpl.nasa.gov/?sat_elem JPL] (site updated 2008 Aug 25)</ref> but more recent reports have been that it is grey like the remaining moons.<ref name="Stern06b">{{cite journal | author=Stern S.A. |display-authors = etal |title=''The Positions, Colors, and Photometric Variability of Pluto's Small Satellites from HST Observations 2005-2006'' |journal=Astronomical Journal |year=2006 |pages=submitted }} ([http://www.arxiv.org/abs/astro-ph/0605014 Final preprint])</ref>

Nix was visited along with Pluto by the ''[[New Horizons]]'' mission in 2015.

The formal name "Nix", from the Greek [[goddess]] of [[darkness]] and [[night]], and mother of Charon, was announced on June 21, 2006 on IAU Circular 8723,<ref name="IAUC8723">[http://www-int.stsci.edu/~mutchler/documents/IAU_Circular_8723.pdf IAU Circular No. 8723] naming the moons</ref> where the designation '''Pluto II''' is also given. Together with Hydra, Pluto's third moon, the initials are those of the ''[[New Horizons]]'' probe. The initial proposal was to use the [[Classical Greek|Classical]] spelling [[Nyx (mythology)|Nyx]], but to avoid confusion with the [[asteroid]] [[3908 Nyx]], this was changed to "the Egyptian<!--Coptic--> spelling of the Greek name".<ref name="Gazetteer">{{cite web
  | title=Planet and Satellite Names and Discoverers
  | work=Gazetteer of Planetary Nomenclature
  | publisher=USGS Astrogeology
  | date=July 21, 2006
  | url=http://planetarynames.wr.usgs.gov/append7.html
  | accessdate=2006-08-15 }}</ref>

== References ==
{{reflist}}

== Other websites ==
* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Plu_Nix Nix Profile] {{Webarchive|url=https://web.archive.org/web/20070801231443/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Plu_Nix |date=2007-08-01 }} by [http://solarsystem.nasa.gov NASA's Solar System exploration]
* [http://www.boulder.swri.edu/plutonews/ Background information regarding our two newly discovered satellites of Pluto] – The discoverers' website
* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2005/19/ NASA's Hubble reveals possible new moons around Pluto] – Hubble press release
* [http://www.space.com/scienceastronomy/051031_pluto_moons.html Two more moons discovered orbiting Pluto] (SPACE.com)
* [http://www.space.com/scienceastronomy/060621_nix_hydra.html Pluto's newest moons named Hydra and Nix] (SPACE.com)
* [{{cite journal|journal=The Astronomical Journal |author=Steffl A.J. |year=2006 |title=New constraints on additional satellites of the Pluto system |url=https://archive.org/details/sim_astronomical-journal_2006-08_132_2/page/614 |volume=132 |issue=2 |pages=614–619 |doi=10.1086/505424 |arxiv=astro-ph/0511837 |bibcode=2006AJ....132..614S |s2cid=10547358 }}([https://arxiv.org/abs/astro-ph/0511837 Final preprint])

{{Moons of Pluto}}

[[Category:Pluto's moons]]