129 Antigone Explained

Minorplanet:yes
Background:
  1. D6D6D6
129 Antigone
Discovered:5 February 1873
Mpc Name:(129) Antigone
Alt Names:A873 CA; 1878 CA;
1907 BA
Pronounced:[1]
Epoch:31 July 2016 (JD 2457600.5)
Semimajor:2.87038AU
Perihelion:2.26344AU
Aphelion:3.4773abbr=onNaNabbr=on
Eccentricity:0.21145
Period:4.86 yr (1776.3 d)
Inclination:12.262°
Asc Node:135.703°
Arg Peri:111.076°
Avg Speed:17.39 km/s
Dimensions:113
119.44 ± 3.91 km
Density:2.96 ± 1.04 g/cm3
Surface Grav:0.0349 m/s2
Escape Velocity:0.0661 km/s
Rotation:4.9572abbr=onNaNabbr=on
Magnitude:9.71 (brightest?)
Abs Magnitude:7.07
Albedo:0.164
Mean Motion: / day
Observation Arc:112.47 yr (41080 d)
Uncertainty:0
Moid:1.2837AU
Jupiter Moid:1.7487AU
Tisserand:3.232

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.

In 1979 a possible satellite of Antigone was suggested based on lightcurve data. 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.

10μ radiometric data collected from Kitt Peak in 1975 gave a diameter estimate of 114 km. 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.

Notes and References

  1. Noah Webster (1884) A Practical Dictionary of the English Language