{{Short description|Outer main-belt asteroid}} {{Use dmy dates|date=April 2018}} {{Infobox planet | minorplanet = yes | name = 22740 Rayleigh | background = #D6D6D6 | image = | image_size = | caption = | discovery_ref = <ref name="jpldata" /> | discoverer = E. W. Elst | discovery_site = La Silla Obs. | discovered = 20 September 1998 | mpc_name = (22740) Rayleigh | alt_names = {{nowrap|{{mp|1998 SX|146}}{{·}}1986 SN}} | pronounced = | named_after = Lord Rayleigh<ref name="MPC-object" /><br />{{small|(English physicist)}} | mp_category = main-belt<ref name="MPC-object" />{{·}}{{small|(outer)}}<ref name="jpldata" /><br />{{nowrap|background<ref name="AstDys-object" />{{·}}Zhongguo<ref name="Roig-2002" />}} | orbit_ref = <ref name="jpldata" /> | epoch = 23 March 2018 (JD 2458200.5) | uncertainty = 0 | observation_arc = 31.32 yr (11,438 d) | aphelion = 3.9380 AU | perihelion = 2.5473 AU | semimajor = 3.2426 AU | eccentricity = 0.2144 | period = 5.84 yr (2,133 d) | mean_anomaly = 200.81° | mean_motion = {{Deg2DMS|0.1688|sup=ms}} / day | inclination = 3.1157° | asc_node = 169.06° | arg_peri = 112.43° | mean_diameter = {{val|9.819|2.434}} km<ref name="Nugent-2015" /> | rotation = | albedo = {{val|0.088|0.081}}<ref name="Nugent-2015" /> | spectral_type = | abs_magnitude = 13.4<ref name="jpldata" /> }}

'''22740 Rayleigh''' (provisional designation '''{{mp|1998 SX|146}}''') is a Zhongguo asteroid from the outermost region of the asteroid belt, approximately {{convert|10|km|mi|abbr=off|sigfig=1|sp=us}} in diameter. It was discovered on 20 September 1998, by Belgian astronomer Eric Elst at the La Silla Observatory in Chile. It is one of few asteroids located in the 2:1 resonance with Jupiter. The asteroid was named for English physicist and Nobel laureate Lord Rayleigh.<ref name="MPC-object" />

== Orbit and classification == Rayleigh is a non-family asteroid from the main belt's background population. It is a member of the small group of Zhongguo asteroids, located in the Hecuba gap (2:1 mean motion resonance with Jupiter) near 3.27&nbsp;AU. Contrary to the nearby unstable Griqua group, the orbits of the Zhongguos are stable over half a billion years.<ref name="AstDys-object" /><ref name="Roig-2002" />

It orbits the Sun in the outer asteroid belt at a distance of 2.5–3.9&nbsp;AU once every 5 years and 10 months (2,133 days; semi-major axis of 3.24&nbsp;AU). Its orbit has an eccentricity of 0.21 and an inclination of 3° with respect to the ecliptic.<ref name="jpldata" /> The body's observation arc begins with its observations as {{mp|1986 SN}} at Klet Observatory in September 1986, or 13 years prior to its official discovery observation at La Silla.<ref name="MPC-object" />

== Physical characteristics ==

=== Diameter and albedo === According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Rayleigh measures 9.819 kilometers in diameter and its surface has an albedo of 0.088.<ref name="Nugent-2015" />

=== Rotation period === As of 2018, no rotational lightcurve of Rayleigh has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown.<ref name="jpldata" /><ref name="lcdb" />

== Naming == This minor planet was named after English physicist John William Strutt, 3rd Baron Rayleigh (Lord Rayleigh; 1842–1919), who discovered the noble gas argon and was awarded the Nobel Prize in Physics in 1904 ''(also see list of laureates)''.<ref name="MPC-object" /> The official naming citation was published by the Minor Planet Center on 1 June 2007 ({{small|M.P.C. 59923}}).<ref name="MPC-Circulars-Archive" /> The lunar crater ''Rayleigh'' as well as the crater ''Rayleigh'' on Mars are also named in his honor.<ref>{{GPN|4966|name=Lunar crater Rayleigh}}</ref><ref>{{GPN|4967|name=Martian crater Rayleigh}}</ref>

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

<ref name="jpldata">{{cite web |type = 2018-01-23 last obs. |title = JPL Small-Body Database Browser: 22740 Rayleigh (1998 SX146) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2022740 |publisher = Jet Propulsion Laboratory |accessdate = 27 April 2018}}</ref>

<ref name="MPC-object">{{cite web |title = 22740 Rayleigh (1998 SX146) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=22740 |accessdate = 31 January 2018}}</ref>

<ref name="MPC-Circulars-Archive">{{cite web |title = MPC/MPO/MPS Archive |work = Minor Planet Center |url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |accessdate = 31 January 2018}}</ref>

<ref name="Nugent-2015">{{cite journal |display-authors = 6 |first1 = C. R. |last1 = Nugent |first2 = A. |last2 = Mainzer |first3 = J. |last3 = Masiero |first4 = J. |last4 = Bauer |first5 = R. M. |last5 = Cutri |first6 = T. |last6 = Grav |first7 = E. |last7 = Kramer |first8 = S. |last8 = Sonnett |first9 = R. |last9 = Stevenson |first10 = E. L. |last10 = Wright |date = December 2015 |title = NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos |journal = The Astrophysical Journal |volume = 814 |issue = 2 |page = 13 |bibcode = 2015ApJ...814..117N |doi = 10.1088/0004-637X/814/2/117 |arxiv = 1509.02522 |s2cid = 9341381 }}</ref>

<ref name="Roig-2002">{{Cite journal |first1 = F. |last1 = Roig |first2 = D. |last2 = Nesvorný |first3 = S. |last3 = Ferraz-Mello |date = September 2002 |title = Asteroids in the 2 : 1 resonance with Jupiter: dynamics and size distribution [ Erratum: 2002MNRAS.336.1391R ] |journal = Monthly Notices of the Royal Astronomical Society |volume = 335 |issue = 2 |pages = 417–431 |bibcode = 2002MNRAS.335..417R |doi = 10.1046/j.1365-8711.2002.05635.x |doi-access = free }}</ref>

<ref name="AstDys-object">{{cite web |title = Asteroid 22740 Rayleigh – Proper Elements |publisher = AstDyS-2, Asteroids – Dynamic Site |url = https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=22740 |access-date= 29 October 2019}}</ref>

<ref name="lcdb">{{cite LCDB|number = 22740 |accessdate = 27 April 2018}}</ref>

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

== External links == * [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }}) * [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books * [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend * [https://www.minorplanetcenter.net/iau/lists/NumberedMPs020001.html Discovery Circumstances: Numbered Minor Planets (20001)-(25000)] – Minor Planet Center * {{AstDys|22740}} * {{JPL small body}}

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{{DEFAULTSORT:Rayleigh}} 022740 022740 Category:Discoveries by Eric Walter Elst Category:Named minor planets 19980920