129 Antigone

Antigone (minor planet designation: 129 Antigone) is a large main-belt asteroid. Radar observations indicate that it is composed of almost pure nickel-iron. It and other similar asteroids probably originate from the core of a shattered Vesta-like planetesimal which had a differentiated interior. It was discovered by German-American astronomer C. H. F. Peters on February 5, 1873, and named after Antigone, the Theban princess in Greek mythology.

129 Antigone
A three-dimensional model of 129 Antigone based on its light curve.
Discovery
Discovered byChristian Heinrich Friedrich Peters
Discovery date5 February 1873
Designations
(129) Antigone
Pronunciation/ænˈtɪɡəniː/[1]
Named after
Antigone
A873 CA; 1878 CA;
1907 BA
Main belt
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc112.47 yr (41080 d)
Aphelion3.4773 AU (520.20 Gm)
Perihelion2.26344 AU (338.606 Gm)
2.87038 AU (429.403 Gm)
Eccentricity0.21145
4.86 yr (1776.3 d)
17.39 km/s
97.3536°
0° 12m 9.619s / day
Inclination12.262°
135.703°
111.076°
Earth MOID1.2837 AU (192.04 Gm)
Jupiter MOID1.7487 AU (261.60 Gm)
TJupiter3.232
Physical characteristics
Dimensions113[2]
119.44 ± 3.91 km[3]
Mass(2.65 ± 0.89) × 1018 kg[3]
Mean density
2.96 ± 1.04 g/cm3[3]
Equatorial surface gravity
0.0349 m/s2
Equatorial escape velocity
0.0661 km/s
4.9572 h (0.20655 d)[2][4]
0.164
Temperature~164 K
M
9.71 (brightest?)
7.07

    In 1979 a possible satellite of Antigone was suggested based on lightcurve data.[5] A model constructed from these shows Antigone itself to be quite regularly shaped. In 1990, the asteroid was observed from the Collurania-Teramo Observatory, allowing a composite light curve to be produced that showed a rotation period of 4.9572 ± 0.0001 hours and a brightness variation of 0.34 ± 0.01 in magnitude. The ratio of the lengths of the major to minor axes for this asteroid were found to be 1.45 ±0.02.[4]

    10μ radiometric data collected from Kitt Peak in 1975 gave a diameter estimate of 114 km.[6] Since 1985, a total of three stellar occultations by Antigone have been observed. A favorable occultation of a star on April 11, 1985, was observed from sites near Pueblo, Colorado, allowing a diameter estimate of 113.0 ± 4.2 km to be calculated.[7]

    References
    1. Noah Webster (1884) A Practical Dictionary of the English Language
    2. Yeomans, Donald K., "129 Antigone", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
    3. Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
    4. Dotto, E.; et al. (June 1992), "M-type asteroids - Rotational properties of 16 objects", Astronomy and Astrophysics Supplement Series, vol. 95, no. 2, pp. 195–211, Bibcode:1992A&AS...95..195D.
    5. Johnston, Wm. Robert (17 February 2013), "Other Reports of Asteroid/TNO Companions", Johnston's Archive, retrieved 29 March 2013.
    6. Morrison, D.; Chapman, C. R. (March 1976), "Radiometric diameters for an additional 22 asteroids", Astrophysical Journal, vol. 204, pp. 934–939, Bibcode:2008mgm..conf.2594S, doi:10.1142/9789812834300_0469.
    7. Wasserman, L. H.; et al. (June 1986), "The Occultation of AG + 20° 1138 by 129 Antigone on 11 April 1985", Bulletin of the American Astronomical Society, vol. 18, p. 797, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009.

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