astro.wikisort.org - Asteroid

66391 Moshup /ˈmɒʃʌp/, provisional designation 1999 KW₄, 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.[3] It is also a Mercury-crosser and the closest known binary system to the Sun with a perihelion of just 0.2 AU.

66391 Moshup

Moshup and its satellite Squannit imaged by the Very Large Telescope's SPHERE instrument[1]
Discovery [2]
Discovered by	LINEAR
Discovery site	Lincoln Lab's ETS
Discovery date	20 May 1999
Designations
Pronunciation	/ˈmɒʃʌp/
Named after	Moshup (Maushop) (native American legend)
Alternative designations	1999 KW4
Minor planet category	Aten · NEO · PHA [2][3] Mercury-crosser Venus-crosser
Orbital characteristics [2]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	19.01 yr (6,942 days)
Aphelion	1.0845 AU
Perihelion	0.2000 AU
Semi-major axis	0.6422 AU
Eccentricity	0.6886
Orbital period (sidereal)	0.51 yr (188 days)
Mean anomaly	359.03°
Mean motion	1° 54m 54s / day
Inclination	38.884°
Longitude of ascending node	244.91°
Argument of perihelion	192.62°
Known satellites	1 (Squannit /ˈskwɒnɪt/)
Earth MOID	0.0138 AU · 5.4 LD
Physical characteristics
Dimensions	1.532 × 1.495 × 1.347 km[4]
Mean diameter	1.317±0.040 km[4]
Mass	(2.49±0.054)×1012 kg[4]
Synodic rotation period	2.7650 h[5]
Geometric albedo	0.26 (derived)[6]
Spectral type	SMASS = S[2][6] V–I=0.85±0.01[7] V–R=0.44±0.02[7] V–I=0.65±0.03[7]
Absolute magnitude (H)	16.5[2][6]

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.[2] 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.[3]

As a potentially hazardous asteroid, it has an Earth minimum orbital intersection distance of 0.0138 AU (2,060,000 km) which corresponds to 5.4 lunar distances.[2] On 25 May 2036, it will pass 0.0155 AU (2,320,000 km) from Earth.[8]

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 naming citation was published by the Minor Planet Center on 27 August 2019 (M.P.C. 115894).[9]

Physical characteristics

In the SMASS classification, the asteroid a characterized as a stony S-type asteroid.[2]

Satellite

Moshup has a minor-planet moon orbiting it. The moon, named Squannit /ˈskwɒnɪt/ and designated S/2001 (66391) 1, is approximately 360 metres in diameter, and orbits its primary in 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 observations and announced on 23 May 2001 (also see below).[5][10] Based on radar imaging, Squannit's dimensions are estimated to be 595 × 450 × 343 meters.[4]

Diameter and shape

According to radiometric observations from Arecibo Observatory, the asteroid has a mean diameter of 1.317 kilometers.[4] 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.[4]

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.[6]

The shapes of the two bodies and their dynamics are complex.[11] With a dimension of approximately 1.42 × 1.36 × 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 at above right, 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",[12] which is now understood to be a very common shape for asteroids in critical rotation,[13] 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 (U=3).[5]

See also

• List of asteroid close approaches to Earth in 2019
• List of solar system objects by size

References

External links

• Margot, Jean-Luc, Radar observations of 1999 KW₄ November 1999, retrieved July 2016
• Near-Earth Asteroid Is Two Chunks In One, NASA Jet Propulsion Laboratory, May 2001
• Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
• 1999 KW4 orbit and observations at IAU Minor Planet Center
• 66391 Moshup at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 66391 Moshup at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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[de] (66391) Moshup

(66391) Moshup (provisorische Bezeichnung 1999 KW4) ist ein erdnaher Asteroid, der die Erdbahn kreuzt und dessen Perihel innerhalb der Merkurbahn liegt. Der Asteroid ist mitsamt seinem Mond Squannit das der Sonne am nächsten liegende Doppelsystem.

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- [en] 66391 Moshup

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[ru] (66391) Мошуп

(66391) Мошуп (лат. Moshup) — околоземный двойной астероид группы Атонов. Относится к потенциально опасным объектам, который может сближаться с Землёй, Венерой и Меркурием из-за параметров своей орбиты, перигелий которой находится в 0,2 а.е., а афелий — в 1,0845 а.е. от Солнца. Ранее имел обозначение (66391) 1999 KW4.

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