4797 Ako
{{Short description|Stony Nysian asteroid from the inner regions of the asteroid belt}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet = yes
| name = 4797 Ako
| background = #D6D6D6
| image =
| image_size =
| caption =
| discovered = 30 September 1989
| discoverer = T. Nomura
K. Kawanishi
| discovery_site = Minami-Oda Obs. ({{small|374}})
| mpc_name = (4797) Ako
| alt_names = 1989 SJ{{·}}{{mp|1978 VY|9}}
{{mp|1985 QB|4}}
| named_after = Akō, Hyōgo
{{small|(Japanese city)}}
| mp_category = main-belt{{·}}Nysa
| epoch = 4 September 2017 (JD 2458000.5)
| uncertainty = 0
| observation_arc = 38.49 yr (14,057 days)
| aphelion = 2.8553 AU
| perihelion = 1.9714 AU
| semimajor = 2.4133 AU
| eccentricity = 0.1831
| period = 3.75 yr (1,369 days)
| mean_anomaly = 146.42°
| mean_motion = {{Deg2DMS|0.2629|sup=ms}} / day
| inclination = 1.8108°
| asc_node = 320.82°
| arg_peri = 78.111°
| dimensions = 4.00 km {{small|(calculated)}}
{{val|6.000|0.496}} km
| rotation = {{val|4.085|0.001}} h
| albedo = {{val|0.112|0.021}}
0.21 {{small|(assumed)}}
| spectral_type = S
| abs_magnitude = 14.1{{·}}14.3{{·}}{{val|14.31|0.27}}
}}
4797 Ako, provisional designation {{mp|1989 SJ}}, is a stony Nysian asteroid from the inner regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 30 September 1989, by the Japanese astronomers Toshiro Nomura and Kōyō Kawanishi at the Minami-Oda Observatory ({{small|374}}), Japan. The asteroid was named for the Japanese city of Akō.
Orbit and classification
Ako is a member of the stony subgroup of the Nysa family, which is named after its largest member 44 Nysa. It orbits the Sun in the inner main-belt at a distance of 2.0–2.9 AU once every 3 years and 9 months (1,369 days). Its orbit has an eccentricity of 0.18 and an inclination of 2° with respect to the ecliptic.
In 1978, it was first identified as {{mp|1978 VY|9}} at Palomar Observatory, extending the body's observation arc by 11 years prior to its official discovery observation at Minami-Oda Observatory.
Physical characteristics
= Rotation period =
A rotational lightcurve of Ako was obtained for the first time from photometric observations made at the U.S. Ricky Observatory, Missouri, in November 2008. It gave a well-defined rotation period of {{val|4.085|0.001}} hours with a relatively high brightness variation of 0.90 in magnitude ({{small|U=3}}), indicative of a non-spheroidal shape.
= Diameter and albedo =
According to NASA's space-based Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Ako measures 6.0 kilometers in diameter and its surface has an albedo of 0.11, while the Collaborative Asteroid Lightcurve Link (CALL) assumes a standard albedo for stony asteroids of 0.21, and calculates a diameter of 4.0 kilometers, as the higher the albedo (reflectivity), the smaller a body's diameter for a certain absolute magnitude (brightness).
Naming
This minor planet was named for the city of Akō in the Hyōgo Prefecture, Japan, and for its ancient castle on the Seto Inland Sea.
Known for its salt production, Ako is the birthplace of the fictional account of Chūshingura, a tale about the forty-seven Ronin who committed seppuku after avenging their master. The city is also the home of the second discoverer's private Minami-Oda observatory, where Kōyō Kawanishi observes small Solar System bodies. The official naming citation was published by the Minor Planet Center on 27 June 1991 ({{small|M.P.C. 18465}}).
References
{{reflist|30em|refs=
|type = 2017-05-01 last obs.
|title = JPL Small-Body Database Browser: 4797 Ako (1989 SJ)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2004797
|publisher = Jet Propulsion Laboratory
|access-date = 20 June 2017}}
|title = Dictionary of Minor Planet Names – (4797) Ako
|last = Schmadel | first = Lutz D.
|publisher = Springer Berlin Heidelberg
|page = 414
|date = 2007
|isbn = 978-3-540-00238-3
|doi = 10.1007/978-3-540-29925-7_4700 |chapter = (4797) Ako }}
|title = 4797 Ako (1989 SJ)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=4797
|access-date = 4 May 2016}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|access-date = 4 May 2016}}
|title = LCDB Data for (4797) Ako
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=4797%7CAko
|access-date = 4 May 2016}}
|display-authors = 6
|first1 = A. |last1 = Mainzer
|first2 = T. |last2 = Grav
|first3 = J. |last3 = Masiero
|first4 = E. |last4 = Hand
|first5 = J. |last5 = Bauer
|first6 = D. |last6 = Tholen
|first7 = R. S. |last7 = McMillan
|first8 = T. |last8 = Spahr
|first9 = R. M. |last9 = Cutri
|first10 = E. |last10 = Wright
|first11 = J. |last11 = Watkins
|first12 = W. |last12 = Mo
|first13 = C. |last13 = Maleszewski
|date = November 2011
|title = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...90M
|journal = The Astrophysical Journal
|volume = 741
|issue = 2
|page = 25
|bibcode = 2011ApJ...741...90M
|doi = 10.1088/0004-637X/741/2/90
|arxiv = 1109.6407
|access-date= 4 May 2016}}
|display-authors = 6
|first1 = Craig |last1 = Bennefeld
|first2 = Stephen |last2 = Bass
|first3 = Ricco |last3 = Blair
|first4 = Kendrick |last4 = Cunningham
|first5 = Da'quia |last5 = Hill
|first6 = Michael |last6 = McHenry
|first7 = Lerone |last7 = Maxwell
|date = October 2009
|title = Asteroid Lightcurve Analysis at Ricky Observatory
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2009MPBu...36..147B
|journal = The Minor Planet Bulletin
|volume = 36
|issue = 4
|pages = 147–148
|issn = 1052-8091
|bibcode = 2009MPBu...36..147B
|access-date= 4 May 2016}}
|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= 4 May 2016}}
|display-authors = 6
|first1 = Joseph R. |last1 = Masiero
|first2 = A. K. |last2 = Mainzer
|first3 = T. |last3 = Grav
|first4 = J. M. |last4 = Bauer
|first5 = R. M. |last5 = Cutri
|first6 = J. |last6 = Dailey
|first7 = P. R. M. |last7 = Eisenhardt
|first8 = R. S. |last8 = McMillan
|first9 = T. B. |last9 = Spahr
|first10 = M. F. |last10 = Skrutskie
|first11 = D. |last11 = Tholen
|first12 = R. G. |last12 = Walker
|first13 = E. L. |last13 = Wright
|first14 = E. |last14 = DeBaun
|first15 = D. |last15 = Elsbury
|first16 = T. IV |last16 = Gautier
|first17 = S. |last17 = Gomillion
|first18 = A. |last18 = Wilkins
|date = November 2011
|title = Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M
|journal = The Astrophysical Journal
|volume = 741
|issue = 2
|page = 20
|bibcode = 2011ApJ...741...68M
|doi = 10.1088/0004-637X/741/2/68
|arxiv = 1109.4096
|access-date= 5 December 2016}}
}}
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/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
- {{AstDys|4797}}
- {{JPL small body}}
{{Minor planets navigator |4796 Lewis |number=4797 |4798 Mercator}}
{{Small Solar System bodies}}
{{Authority control}}
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Category:Discoveries by Toshiro Nomura