1355 Magoeba

1355 Magoeba, provisional designation 1935 HE, is a Hungaria asteroid and a suspected contact-binary from the innermost regions of the asteroid belt, approximately 5 kilometers in diameter. It was discovered on 30 April 1935, by English-born, South African astronomer Cyril Jackson at the Johannesburg Observatory in South Africa.[3] The asteroid is named for Magoeba, a tribal chief in the South African Transvaal Province.[2]

1355 Magoeba
Discovery[1]
Discovered byC. Jackson
Discovery siteJohannesburg Obs.
Discovery date30 April 1935
Designations
(1355) Magoeba
Named after
Magoeba
(South African chief)[2]
1935 HE
main-belt · Hungaria[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc81.71 yr (29,843 days)
Aphelion1.9363 AU
Perihelion1.7707 AU
1.8535 AU
Eccentricity0.0447
2.52 yr (922 days)
245.86°
0° 23m 26.16s / day
Inclination22.827°
225.25°
340.40°
Physical characteristics
Dimensions4.276±0.170 km[5]
4.828±0.094 km[6]
5.96 km (calculated)[4]
2.9712±0.0003 h[7]
2.972±0.002 h[8]
2.975±0.002 h[8]
5.946±0.005 h[9]
5.99±0.05 h[10][lower-alpha 1]
31.65±0.05 h[9]
32.9±0.1 h[11]
0.267±0.095[12]
0.3 (assumed)[4]
0.4663±0.0824[6]
0.582±0.049[5]
Tholen = X[1] · M[13] · E[6] · X[4]
B–V = 0.713[1]
U–B = 0.255[1]
13.02±0.22[14] · 13.05[1][4][6]

    Orbit and classification

    Magoeba is a member of the Hungaria family, which forms the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt at a distance of 1.8–1.9 AU once every 2 years and 6 months (922 days). Its orbit has an eccentricity of 0.04 and an inclination of 23° with respect to the ecliptic.[1] The first precovery was taken at Nice Observatory just 3 day prior to its official discovery. The body's observation arc begins at Johannesburg the night after its discovery observation.[3]

    Physical characteristics

    Lightcurves

    Between 2006 and 2014, several rotational lightcurves of Magoeba were obtained by American astronomer Brian Warner at the CS3–Palmer Divide Station (U82) in California. Lightcurve analysis of the photometric observations taken during the asteroid's 2014-apparition gave a rotation period of 2.971 hours with a brightness variation of 0.09 magnitude (U=3).[7][lower-alpha 2]

    Previously derived periods varied strongly (5.99 and 31.65 hours) with alternative period solutions (U=2-/2/2).[9][10][11][lower-alpha 1] The Observation were taken at the Palmer Divide Observatory (716) in Colorado (see video in § External links). It is now suspected that this discrepancy might be caused by the presence of an asteroid moon that orbits Magoeba with a period of 15.05 hours.[7]

    Diameter and albedo

    According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Magoeba measures 4.276 and 4.828 kilometers in diameter, and its surface has an albedo of 0.582 and 0.466, respectively,[5][6] while a polarimetric study of Hungaria asteroids found a lower albedo of 0.267.[12] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between 0.4 and 0.2, corresponding to the Hungaria asteroids both as family and orbital group – and calculates a diameter of 5.96 kilometers with an absolute magnitude of 13.05.[4]

    Spectral type

    In the Tholen taxonomy, Magoeba is an X-type asteroid, which can be further divided into the bright E, the metallic M and the carbonaceous P classes, with similar spectra but very different inferred mineralogies.[13] It has both been classified as an E-type asteroid by the WISE/NEOWISE mission, and as a M-type asteroid by a dedicated spectroscopic survey at the Argentinian Lencito Complex, respectively.[6][13]

    Naming

    This minor planet was named for Magoeba, a native chief of the North Transvaal in South Africa.[2] The official naming citation was published by the Minor Planet Center in April 1953 (M.P.C. 908).[15]

    Notes
    1. Lightcurve plot of (1355) Magoeba, Palmer Divide Observatory, B. D. Warner (2011)
    2. Light-curve plots of (1355) Magoeba from the 2013-observation and from the 2014-observation, published by the Center for Solar System Studies (CS3) in Landers, California.

    References
    1. "JPL Small-Body Database Browser: 1355 Magoeba (1935 HE)" (2017-01-09 last obs.). Jet Propulsion Laboratory. Retrieved 25 July 2017.
    2. Schmadel, Lutz D. (2007). "(1355) Magoeba". Dictionary of Minor Planet Names – (1355) Magoeba. Springer Berlin Heidelberg. p. 110. doi:10.1007/978-3-540-29925-7_1356. ISBN 978-3-540-00238-3.
    3. "1355 Magoeba (1935 HE)". Minor Planet Center. Retrieved 13 January 2017.
    4. "LCDB Data for (1355) Magoeba". Asteroid Lightcurve Database (LCDB). Retrieved 13 January 2017.
    5. Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 13 January 2017.
    6. Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90.
    7. Warner, Brian D. (January 2015). "A Sextet of Main-belt Binary Asteroid Candidates". The Minor Planet Bulletin. 42 (1): 60–66. Bibcode:2015MPBu...42...60W. ISSN 1052-8091. Retrieved 13 January 2017.
    8. Warner, Brian D. (October 2013). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2013 May-June". The Minor Planet Bulletin. 40 (4): 208–212. Bibcode:2013MPBu...40..208W. ISSN 1052-8091. Retrieved 13 January 2017.
    9. 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 13 January 2017.
    10. Warner, Brian D. (October 2011). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2011 March - July". The Minor Planet Bulletin. 38 (4): 190–195. Bibcode:2011MPBu...38..190W. ISSN 1052-8091. Retrieved 13 January 2017.
    11. Warner, Brian D. (March 2007). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory - June-September 2006". The Minor Planet Bulletin. 34 (1): 8–10. Bibcode:2007MPBu...34....8W. ISSN 1052-8091. Retrieved 13 January 2017.
    12. Gil-Hutton, R.; Lazzaro, D.; Benavidez, P. (June 2007). "Polarimetric observations of Hungaria asteroids". Astronomy and Astrophysics. 468 (3): 1109–1114. Bibcode:2007A&A...468.1109G. doi:10.1051/0004-6361:20077178. Retrieved 13 January 2017.
    13. Fornasier, S.; Clark, B. E.; Dotto, E. (July 2011). "Spectroscopic survey of X-type asteroids". Icarus. 214 (1): 131–146. arXiv:1105.3380. Bibcode:2011Icar..214..131F. doi:10.1016/j.icarus.2011.04.022. Retrieved 13 January 2017.
    14. 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 13 January 2017.
    15. 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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