1750 Eckert

1750 Eckert, provisional designation 1950 NA1, is a stony slow rotating Hungaria asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 15 July 1950, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany.[3] It was named after American astronomer Wallace Eckert.[2]

1750 Eckert
Shape model of Eckert from its lightcurve
Discovery[1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date15 July 1950
Designations
(1750) Eckert
Named after
Wallace Eckert
(astronomer)[2]
1950 NA1 · 1950 OA
Mars-crosser[1] · Hungaria[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc66.89 yr (24,431 days)
Aphelion2.2597 AU
Perihelion1.5932 AU
1.9265 AU
Eccentricity0.1730
2.67 yr (977 days)
346.00°
Inclination19.084°
273.76°
109.00°
Earth MOID0.6934 AU
Physical characteristics
Dimensions6.95±0.21 km[4]
6.97 km (calculated)[5]
4.49±0.01 h (dated)[6]
375±5 h[7]
377.5±0.5 h[8]
0.20 (assumed)[5]
0.203±0.013[4]
B–V = 0.885[1]
U–B = 0.500[1]
Tholen = S[1] · S[5]
13.15[1][4][5] · 13.67±0.33[9]

    Classification and orbit

    The Mars crossing asteroid is also a member of the Hungaria family, a group that forms the innermost dense concentration of asteroids in the Solar System. It orbits the Sun at a distance of 1.6–2.3 AU once every 2 years and 8 months (977 days). Its orbit has an eccentricity of 0.17 and an inclination of 19° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, Eckert's observation arc begins with its official discovery observation.[3]

    Rotation period

    In October 2009, a rotational lightcurve of Eckert was obtained by American astronomer Brian Warner at his Palmer Divide Observatory (716) in Colorado. It gave an exceptionally long rotation period of 375 hours with a brightness variation of 0.87 magnitude (U=3-).[7] A modeled lightcurve obtained from the Lowell Photometric Database in 2016, gave a similar period of 377.5 hours (U=n.a.).[8] Eckert has the sixth-longest rotation period of all known Mars-crossers.[10]

    Diameter and albedo

    According to the survey carried out by the Japanese Akari satellite, the asteroid measures 6.95 kilometers in diameter, and its surface has an albedo of 0.203.[4] The Collaborative Asteroid Lightcurve Link agrees with Akarai and assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 6.97 kilometers with an absolute magnitude of 13.15.[5]

    Naming

    The minor planet was named in memory of American astronomer Wallace Eckert (1902–1971), director at the United States Naval Observatory from 1940 to 1945, president of IAU's Commission 7, and pioneer in the use of automatic computing machines. In the late 1940s and early 1950s, he used the then most powerful computing machines ever built, SSEC and NORC, for astronomical calculations. The asteroid 1625 The NORC was named after one of these early super-computers. Eckert also produced the integration of the orbits of the five outer planets in collaboration with Brouwer and Clemence, after whom the minor planets 1746 Brouwer and 1919 Clemence were named. By use of sophisticated computing techniques, Eckert was able to check and extend Brown's lunar theory (also see 1643 Brown).[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3934).[11]

    References
    1. "JPL Small-Body Database Browser: 1750 Eckert (1950 NA1)" (2017-06-04 last obs.). Jet Propulsion Laboratory. Retrieved 1 July 2017.
    2. Schmadel, Lutz D. (2007). "(1750) Eckert". Dictionary of Minor Planet Names – (1750) Eckert. Springer Berlin Heidelberg. p. 139. doi:10.1007/978-3-540-29925-7_1751. ISBN 978-3-540-00238-3.
    3. "1750 Eckert (1950 NA1)". Minor Planet Center. Retrieved 20 December 2016.
    4. Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
    5. "LCDB Data for (1750) Eckert". Asteroid Lightcurve Database (LCDB). Retrieved 20 December 2016.
    6. Bonzo, Dimitrij; Carbognani, Albino (July 2010). "Lightcurves and Periods for Asteriods [sic] 1001 Gaussia, 1060 Magnolia, 1750 Eckert, 2888 Hodgson, and 3534 Sax". The Minor Planet Bulletin. 37 (3): 93–95. Bibcode:2010MPBu...37...93B. ISSN 1052-8091. Retrieved 20 December 2016.
    7. Warner, Brian D. (April 2010). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 September-December". The Minor Planet Bulletin. 37 (2): 57–64. Bibcode:2010MPBu...37...57W. ISSN 1052-8091. Retrieved 20 December 2016.
    8. Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441. Retrieved 20 December 2016.
    9. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 20 December 2016.
    10. "JPL Small-Body Database Search Engine: orbital class (MCA) and rot_per > 0 (h)". JPL Solar System Dynamics. Retrieved 20 December 2015.
    11. Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.

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