{{Short description|Rare-type Mars-crossing asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | name = 10502 Armaghobs | background = #FA8072 | image = | image_size = | caption = | discovery_ref = <ref name="jpldata" /> | discovered = 22 August 1987 | discoverer = E. F. Helin | discovery_site = Palomar Obs. | mpc_name = (10502) Armaghobs | alt_names = {{mp|1987 QF|6}}{{·}}{{mp|1980 PJ|2}}<br />{{mp|1994 RJ|29}} | pronounced = {{IPAc-en|ɑr|ˈ|m|ɑː|ə|b|z}} {{respell|ar|MAH|əbs}} | named_after = Armagh Observatory<br />{{small|(in Northern Ireland)}}<ref name="springer" /> | mp_category = Mars-crosser<ref name="lcdb" /> | orbit_ref = <ref name="jpldata" /> | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 36.73 yr (13,416 days) | aphelion = 3.0439 AU | perihelion = 1.5745 AU | semimajor = 2.3092 AU | eccentricity = 0.3182 | period = 3.51 yr (1,282 days) | mean_anomaly = 145.86° | mean_motion = {{Deg2DMS|0.2809|sup=ms}} / day | inclination = 21.927° | asc_node = 170.23° | arg_peri = 263.26° | dimensions = {{val|2.61|0.59}} km<ref name="Nugent-2016" /><br />2.97 km {{small|(calculated)}}<ref name="lcdb" /> | rotation = {{val|24.978|0.002}} h<ref name="Hills-2014a" /> | albedo = 0.20 {{small|(assumed)}}<ref name="lcdb" /><br />{{val|0.22|0.14}}<ref name="Nugent-2016" /> | spectral_type = S<ref name="lcdb" />{{·}}Q<ref name="Veres-2015" /> | abs_magnitude = 15.0<ref name="jpldata" /><ref name="lcdb" />{{·}}15.18{{·}}{{val|15.44|0.08}}<ref name="Veres-2015" /> }}
'''10502 Armaghobs''' ({{IPAc-en|ɑr|ˈ|m|ɑː|ə|b|z}} {{respell|ar|MAH|əbz}}), provisional designation {{mp|1987 QF|6}}, is an eccentric, rare-type stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 2.6 kilometers in diameter. The asteroid was discovered on 22 August 1987, by American astronomer Eleanor Helin at the Palomar Observatory in California, United States.<ref name="MPC-Armaghobs" /> It was named for the Armagh Observatory in Northern Ireland.<ref name="springer" />
== Orbit and classification ==
''Armaghobs'' orbits the Sun in the inner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,282 days). Its orbit has an eccentricity of 0.32 and an inclination of 22° with respect to the ecliptic.<ref name="jpldata" /> It was first identified as {{mp|1980 PJ|2}} at ESO's La Silla Observatory in 1980, extending the body's observation arc by 7 years prior to its official discovery observation at Palomar.<ref name="MPC-Armaghobs" />
== Physical characteristics ==
The ''Armaghobs'' has been characterized as a relatively rare Q-type asteroid by Pan-STARRS photometric survey.<ref name="Veres-2015" />
=== Lightcurve ===
In February 2013, a rotational lightcurve of ''Armaghobs'' was obtained from photometric observations by Kevin Hills at the ''Riverland Dingo Observatory'' at Moorook, South Australia. Lightcurve analysis gave a rotation period of {{val|24.978}} hours with a brightness variation of 0.51 magnitude ({{small|U=2}}).<ref name="Hills-2014a" />
=== Diameter and albedo ===
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, ''Armaghobs'' measures 2.61 kilometers in diameter and its surface has an albedo of 0.22.<ref name="Nugent-2016" /> The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20, and calculates a diameter of 2.97 kilometers with an absolute magnitude of 15.0.<ref name="lcdb" />
== Naming ==
This minor planet was named after the Armagh Observatory in Northern Ireland. The present-day astronomical research institute was founded by Archbishop Richard Robinson in 1790. The Estonian astronomer Ernst Öpik, after whom 2099 Öpik is named, had been a long-time member of the Observatory. It is also known for the invention of the cup-anemometer by Thomas Robinson, the ''New General Catalogue'' compiled by John Dreyer, and Lindsay's ''Armagh-Dunsink-Harvard telescope''.<ref name="springer" /> The official naming citation was published by the Minor Planet Center on 9 January 2001 {{small|(M.P.C. 41937)}}.<ref name="MPC-Circulars-Archive" />
== References == {{reflist|30em|refs=
<ref name="jpldata">{{cite web |type = 2017-05-04 last obs. |title = JPL Small-Body Database Browser: 10502 Armaghobs (1987 QF6) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2010502 |publisher = Jet Propulsion Laboratory |accessdate = 23 June 2017}}</ref>
<ref name="springer">{{cite book |title = Dictionary of Minor Planet Names – (10502) Armaghobs |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |page = 736 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_8003 |chapter = (10502) Armaghobs }}</ref>
<ref name="MPC-Armaghobs">{{cite web |title = 10502 Armaghobs (1987 QF6) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=10502 |accessdate = 28 April 2016}}</ref>
<ref name="lcdb">{{cite LCDB|number = 10502 |accessdate = 28 April 2016}}</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 = 28 April 2016}}</ref>
<ref name="Hills-2014a">{{Cite journal |author = Hills, Kevin |date = January 2014 |title = Asteroid Lightcurve Analysis at Riverland Dingo Observatory (RDO): 2013 Results |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014MPBu...41....2H |journal = The Minor Planet Bulletin |volume = 41 |issue = 1 |pages = 2–3 |issn = 1052-8091 |bibcode = 2014MPBu...41....2H |access-date= 28 April 2016}}</ref>
<ref name="Veres-2015">{{cite journal |display-authors = 6 |first1 = Peter |last1 = Veres |first2 = Robert |last2 = Jedicke |first3 = Alan |last3 = Fitzsimmons |first4 = Larry |last4 = Denneau |first5 = Mikael |last5 = Granvik |first6 = Bryce |last6 = Bolin |first7 = Serge |last7 = Chastel |first8 = Richard J. |last8 = Wainscoat |first9 = William S. |last9 = Burgett |first10 = Kenneth C. |last10 = Chambers |first11 = Heather |last11 = Flewelling |first12 = Nick |last12 = Kaiser |first13 = Eugen A. |last13 = Magnier |first14 = Jeff S. |last14 = Morgan |first15 = Paul A. |last15 = Price |first16 = John L. |last16 = Tonry |first17 = Christopher |last17 = Waters |date = November 2015 |title = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V |journal = Icarus |volume = 261 |pages = 34–47 |bibcode = 2015Icar..261...34V |doi = 10.1016/j.icarus.2015.08.007 |arxiv = 1506.00762 |access-date= 28 April 2016}}</ref>
<ref name="Nugent-2016">{{cite journal |display-authors = 6 |first1 = C. R. |last1 = Nugent |first2 = A. |last2 = Mainzer |first3 = J. |last3 = Bauer |first4 = R. M. |last4 = Cutri |first5 = E. A. |last5 = Kramer |first6 = T. |last6 = Grav |first7 = J. |last7 = Masiero |first8 = S. |last8 = Sonnett |first9 = E. L. |last9 = Wright |date = September 2016 |title = NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos |journal = The Astronomical Journal |volume = 152 |issue = 3 |page = 12 |bibcode = 2016AJ....152...63N |doi = 10.3847/0004-6256/152/3/63 |arxiv = 1606.08923 |doi-access = free }}</ref>
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== 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/NumberedMPs010001.html Discovery Circumstances: Numbered Minor Planets (10001)-(15000)] – Minor Planet Center * {{AstDys|10502}} * {{JPL small body}}
{{Minor planets navigator |10501 Ardmacha |number=10502 |(10503) 1987 SG13}} {{Small Solar System bodies}} {{Authority control}}
{{DEFAULTSORT:Armaghobs}} 010502 Armaghobs Category:Named minor planets 19870822