66391 Moshup
{{Short description|Binary near-Earth asteroid}}
{{Infobox planet
| minorplanet = yes
| name = 66391 Moshup
| background = #FFC2E0
| image = 1999kw4 vlt-eso1910.jpg
| image_scale =
| caption = Moshup and its satellite Squannit imaged by the Very Large Telescope's SPHERE instrument
| discovered = 20 May 1999
| discoverer = LINEAR
| discovery_site = Lincoln Lab's ETS
| alt_names = {{mp|1999 KW|4}}
| pronounced = {{IPAc-en|'|m|Q|S|V|p}}
| named_after = Maushop
{{small|(native American legend)}}
| mp_category = Aten{{·}}NEO{{·}}PHA
Mercury-crosser
Venus-crosser
| epoch = 4 September 2017 (JD 2458000.5)
| uncertainty = 0
| observation_arc = 19.01 yr (6,942 days)
| aphelion = 1.0845 AU
| perihelion = 0.2000 AU
| semimajor = 0.6422 AU
| eccentricity = 0.6886
| period = 0.51 yr (188 days)
| mean_anomaly = 359.03°
| mean_motion = {{Deg2DMS|1.9150|sup=ms}} / day
| inclination = 38.884°
| asc_node = 244.91°
| arg_peri = 192.62°
| moid = 0.0138 AU{{·}}5.4 LD
| satellites = 1 (Squannit {{IPAc-en|ˈ|s|k|w|ɒ|n|ᵻ|t}})
| dimensions = {{val|1.532|x|1.495|x|1.347}} km
| mean_diameter = {{val|1.317|0.040|u=km}}
| rotation = {{val|2.7650}} h
| albedo = 0.26 {{small|(derived)}}
| mass = {{val|2.49|0.054|e=12|u=kg}}
| density = {{val|1.97|0.24|u=g/cm3}}
| spectral_type = SMASS = S
B–V={{val|0.85|0.01}}
V–R={{val|0.44|0.02}}
V–I={{val|0.65|0.03}}
}}
66391 Moshup {{IPAc-en|'|m|Q|S|V|p}}, provisional designation {{mp|1999 KW|4}}, is a binary asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Aten group, approximately 1.3 kilometers in diameter. It was discovered on 20 May 1999, by Lincoln Near-Earth Asteroid Research (LINEAR) at the Lincoln Laboratory's Experimental Test Site in Socorro, New Mexico, United States. It is a Mercury-crosser that comes extremely close to the Sun at a perihelion of 0.2 AU.
Orbit
The asteroid orbits the Sun at a distance of 0.2–1.1 AU once every 6.18 months (188 days). Its orbit has an eccentricity of 0.69 and an inclination of 39° with respect to the ecliptic. A first precovery was taken by 2MASS at the Fred Lawrence Whipple Observatory in 1998, extending the body's observation arc by one year prior to its official discovery observation at Socorro.
As a potentially hazardous asteroid, it has an Earth minimum orbital intersection distance of {{convert |0.0138|AU|km| abbr=on |sigfig=3}}, or 5.4 lunar distances. On 25 May 2036, it will pass {{convert |0.0155|AU|km| abbr=on |sigfig=3}} from Earth.
Numbering and naming
This minor planet was numbered by the Minor Planet Center on 10 September 2003. It was named from Mohegan legend, after Moshup, a giant who lived in the coastal areas of New England. The asteroid's companion is named Squannit, after the wife of Moshup and a medicine woman of the Makiawisug (little people). The official {{MoMP|66391|naming citation}} was published by the Minor Planet Center on 27 August 2019 ({{small|M.P.C. 115894}}).
Physical characteristics
In the SMASS classification, the asteroid a characterized as a stony S-type asteroid.
= Satellite =
Moshup has a minor-planet moon orbiting it. The moon, named Squannit {{IPAc-en|ˈ|s|k|w|ɒ|n|ᵻ|t}} and designated {{mp|S/2001 (66391) 1}}, is approximately 360 metres in diameter, and orbits its primary every 16 hours at a mean distance of 2.6 kilometers. The presence of a companion was suggested by photometric observations made by Pravec and Šarounová and was confirmed by radar observations from Arecibo, announced on 23 May 2001 (also see below). Based on radar imaging, Squannit's dimensions are estimated to be {{val|595|x|450|x|343}} meters.
= Diameter and shape =
File:1999KW4 Arecibo 2019May29-31.png
According to radiometric observations from Arecibo Observatory, the asteroid has an effective mean diameter of 1.317 kilometers. The observations were taken from May 21–23, 2001, by Lance A. M. Benner, Steven J. Ostro, Jon D. Giorgini, Raymond F. Jurgens, Jean-Luc Margot and Michael C. Nolan.
The Collaborative Asteroid Lightcurve Link adopts a diameter of 1.3 kilometers and derives an albedo 0.26 with an absolute magnitude of 16.5.
The shapes of the two bodies and their dynamics are complex.NASA Jet Propulsion Laboratory [http://echo.jpl.nasa.gov/ Asteroid Radar Research] {{Webarchive|url=https://web.archive.org/web/20071207175748/http://echo.jpl.nasa.gov/ |date=2007-12-07 }}, retrieved May 3, 2007 With a dimension of approximately {{val|1.42|x|1.36|x|1.18}} kilometers for a simple triaxial ellipsoid, the asteroid has an oblate shape, which is dominated by an equatorial ridge at the body's potential-energy minimum. This bizarre property of the equatorial region means that it is close to breakup: raising a particle a meter above the surface would put it into orbit. As seen in the image above, the gravitational effects between the moon and the asteroid create a gigantic mountain extending in the equatorial plane around the entire asteroid. It was the first asteroid to be described as "muffin-shaped",{{Cite web |title=Scientist: Asteroid To Return In 2036 |url=https://www.cbsnews.com/news/scientist-asteroid-to-return-in-2036/ |access-date=2022-09-27 |website=www.cbsnews.com |date=4 December 2006 |language=en-US}} which is now understood to be a very common shape for asteroids in critical rotation,{{cite journal|last1=Jewitt|first1=David|last2=Weaver|first2=Harold|last3=Mutchler|first3=Max|last4=Li|first4=Jing|last5=Agarwal|first5=Jessica|last6=Larson|first6=Stephen|title=The Nucleus of Active Asteroid 311P/(2013 P5) PANSTARRS|journal=The Astronomical Journal|volume=155|issue=6|year=2018|pages=231|issn=1538-3881|doi=10.3847/1538-3881/aabdee|arxiv=1804.05897 |bibcode=2018AJ....155..231J |doi-access=free }} including 101955 Bennu and 162173 Ryugu.
= Lightcurves =
During 19–27 June 2000, a rotational lightcurve of this asteroid was obtained from photometric observations by Petr Pravec and Lenka Šarounová at Ondřejov Observatory. Lightcurve analysis gave a rotation period of 2.7650 hours with a brightness variation of 0.12 magnitude ({{small|U=3}}).
See also
References
{{reflist|30em| refs =
|type = 2017-05-31 last obs.
|title = JPL Small-Body Database Browser: 66391 (1999 KW4)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2066391;cad=1
|publisher = Jet Propulsion Laboratory
|access-date = 1 June 2017}}
|title = 66391 (1999 KW4)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=66391
|access-date = 30 March 2017}}
|title = MPC/MPO/MPS Archive
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
|access-date = 24 February 2018}}
|display-authors = 6
|first1 = Steven. J. |last1 = Ostro
|first2 = Jean-Luc |last2 = Margot
|first3 = Lance A. M. |last3 = Benner
|first4 = Jon D. |last4 = Giorgini
|first5 = Daniel J. |last5 = Scheeres
|first6 = Eugene G. |last6 = Fahnestock
|first7 = Stephen B. |last7 = Broschart
|first8 = Julie |last8 = Bellerose
|first9 = Michael C. |last9 = Nolan
|first10 = Christopher |last10 = Magri
|first11 = Petr |last11 = Pravec
|first12 = Petr |last12 = Scheirich
|first13 = Randy |last13 = Rose
|first14 = Raymond F. |last14 = Jurgens
|first15 = Eric M. |last15 = De Jong
|first16 = Shigeru |last16 = Suzuki
|date = November 2006
|title = Radar Imaging of Binary Near-Earth Asteroid (66391) 1999 KW4
|url = http://www2.ess.ucla.edu/~jlm/publications/Ostro06.science314.kw4.pdf
|journal = Science
|volume = 314
|issue = 5803
|pages = 1276–1280
|bibcode = 2006Sci...314.1276O
|doi = 10.1126/science.1133622
|access-date= 1 June 2017 |pmid=17038586|s2cid = 10927967 }}
|first1 = Robert |last1 = Johnston
|title = (66391) Moshup and Squannit
|website = Johnston's Archive
|date = 20 October 2019
|url = http://www.johnstonsarchive.net/astro/astmoons/am-66391.html
|access-date = 30 March 2017}}
|type = 2013-05-09 last obs (arc=14.9 yr)
|title = JPL Close-Approach Data: 66391 (1999 KW4)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1999KW4;cad=1#cad
|access-date = 6 April 2016}}
|title = LCDB Data for (66391)
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=66391%7C
|access-date = 1 June 2017}}
|display-authors = 6
|first1 = P. |last1 = Pravec
|first2 = P. |last2 = Scheirich
|first3 = P. |last3 = Kusnirák
|first4 = L. |last4 = Sarounová
|first5 = S. |last5 = Mottola
|first6 = G. |last6 = Hahn
|first7 = P. |last7 = Brown
|first8 = G. |last8 = Esquerdo
|first9 = N. |last9 = Kaiser
|first10 = Z. |last10 = Krzeminski
|first11 = D. P. |last11 = Pray
|first12 = B. D. |last12 = Warner
|first13 = A. W. |last13 = Harris
|first14 = M. C. |last14 = Nolan
|first15 = E. S. |last15 = Howell
|first16 = L. A. M. |last16 = Benner
|first17 = J.-L. |last17 = Margot
|first18 = A. |last18 = Galád
|first19 = W. |last19 = Holliday
|first20 = M. D. |last20 = Hicks
|first21 = Yu. N. |last21 = Krugly
|first22 = D. |last22 = Tholen
|first23 = R. |last23 = Whiteley
|first24 = F. |last24 = Marchis
|first25 = D. R. |last25 = DeGraff
|first26 = A. |last26 = Grauer
|first27 = S. |last27 = Larson
|first28 = F. P. |last28 = Velichko
|first29 = W. R. |last29 = Cooney
|first30 = R. |last30 = Stephens
|first31 = J. |last31 = Zhu
|first32 = K. |last32 = Kirsch
|first33 = R. |last33 = Dyvig
|first34 = L. |last34 = Snyder
|first35 = V. |last35 = Reddy
|first36 = S. |last36 = Moore
|first37 = S. |last37 = Gajdos
|first38 = J. |last38 = Világi
|first39 = G. |last39 = Masi
|first40 = D. |last40 = Higgins
|first41 = G. |last41 = Funkhouser
|first42 = B. |last42 = Knight
|first43 = S. |last43 = Slivan
|first44 = R. |last44 = Behrend
|first45 = M. |last45 = Grenon
|first46 = G. |last46 = Burki
|first47 = R. |last47 = Roy
|first48 = C. |last48 = Demeautis
|first49 = D. |last49 = Matter
|first50 = N. |last50 = Waelchli
|first51 = Y. |last51 = Revaz
|first52 = A. |last52 = Klotz
|first53 = M. |last53 = Rieugné
|first54 = P. |last54 = Thierry
|first55 = V. |last55 = Cotrez
|first56 = L. |last56 = Brunetto
|first57 = G. |last57 = Kober
|date = March 2006
|title = Photometric survey of binary near-Earth asteroids
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2006Icar..181...63P
|journal = Icarus
|volume = 181
|issue = 1
|pages = 63–93
|bibcode = 2006Icar..181...63P
|doi = 10.1016/j.icarus.2005.10.014
|access-date= 1 June 2017}}
|url = https://www.eso.org/public/news/eso1910/
|title = ESO contributes to protecting Earth from dangerous asteroids
|publisher = European Southern Observatory
|date = 3 June 2019
|access-date = 3 June 2019}}
|title = The Color Indices of the NEA (66391) 1999 KW4
|first = Albino |last = Carbognani
|journal = The Minor Planet Bulletin
|volume = 46
|issue = 4
|page = 444
|date = October 2019
|bibcode = 2019MPBu...46..444C
|issn = 1052-8091}}
}}
External links
{{Commons}}
- Margot, Jean-Luc, [http://mel.epss.ucla.edu/jlm/research/NEAs/1999KW4/ Radar observations of {{mp|1999 KW|4}}] November 1999, retrieved July 2016
- [https://www.jpl.nasa.gov/news/news.php?feature=6133 Near-Earth Asteroid Is Two Chunks In One], NASA Jet Propulsion Laboratory, May 2001
- [http://www.johnstonsarchive.net/astro/asteroidmoons.html Asteroids with Satellites], Robert Johnston, johnstonsarchive.net
- [https://www.minorplanetcenter.net/db_search/show_object?object_id=1999+KW4 1999 KW4 orbit and observations] at IAU Minor Planet Center
- {{NeoDys|66391}}
- {{JPL small body|id=66391}}
{{2019 in space}}
{{Minor planets navigator |number=66391 |PageName=66391 Moshup }}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Moshup}}
Category:Earth-crossing asteroids
Category:Mercury-crossing asteroids