71 Niobe

Main-belt asteroid From Wikipedia, the free encyclopedia

71 Niobe[b] is a stony Gallia asteroid and relatively slow rotator from the central regions of the asteroid belt, approximately 90 kilometers (56 miles) in diameter. It was discovered by the German astronomer Robert Luther on 13 August 1861, and named after Niobe, a character in Greek mythology. In 1861, the brightness of this asteroid was shown to vary by astronomer Friedrich Tietjen.[22]

DiscoveredbyR. Luther
DiscoverysiteDüsseldorf Obs.
Discoverydate13 August 1861
(71) Niobe
Quick facts Discovery, Discovered by ...
71 Niobe
Lightcurve-based 3D-model of Niobe
Discovery[1]
Discovered byR. Luther
Discovery siteDüsseldorf Obs.
Discovery date13 August 1861
Designations
(71) Niobe
Pronunciation/ˈnaɪəbiː/[2]
Named after
Νιόβη Niobē (Greek mythology)[3]
main-belt[1][4] · (middle)
Gallia[5]
AdjectivesNiobean /naɪəˈbiːən/[2]
Orbital characteristics[4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc154.10 yr (56,286 d)
Aphelion3.2348 AU
Perihelion2.2790 AU
2.7569 AU
Eccentricity0.1733
4.58 yr (1,672 d)
178.02°
0° 12m 55.08s / day
Inclination23.259°
316.02°
266.88°
Physical characteristics
75.87±3.28 km[6]
80.86±0.80 km[7]
83.42±1.7 km[8]
92.75 km (taken)[9]
92.753 km[10]
92.842±0.644 km[11]
11 h[12]
11.21 h[13]
14.34±0.05 h[14]
14.34 h[15][14]
14.38±0.02 h[16]
35.5±0.1 h[17][a]
35.617948 h[9]
35.81±0.01 h[18]
35.8521±0.0005 h[19]
35.864±0.002 h[20]
0.2446[10]
0.2475±0.0346[11]
0.3052±0.013[8]
0.326±0.008[7]
0.369±0.033[6]
Tholen = S[4]
SMASS = Xe[4] · M[11] · A[21] · X[9]
B–V = 0.803[4]
U–B = 0.439[4]
7.30[4][6][7][8][11]
7.31[9]
7.31±0.09[10][16]
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    Description

    Niobe is a member of the Gallia family (802), a small family of nearly 200 known stony asteroids.[23]

    In 2006, it was examined by radar using the Arecibo Observatory radio telescope in Puerto Rico. This was supplemented by optical observations intended to build a lightcurve. The resulting estimated rotation period of 35.6 hours, or 1.48 Earth days, superseded an earlier estimate of the rotation period as 14.3 hours. The radar data produced an estimate of a maximum equatorial diameter of 94 km, which is consistent with earlier estimates based upon infrared data if the shape is assumed to be slightly elongated.[17][a]

    The rotation period was further refined to 35.864 ± 0.001 hours during observations through 2010. Six stellar occultations of this asteroid between 2004 and 2007 produced chords ranging from 13 to 72 km (8.1 to 44.7 mi), which are statistically consistent with the published maximum diameter estimates.[20]

    Notes

    1. [a]
      Lightcurve plot of 71 Niobe, Palmer Divide Observatory, B. D. Warner (2006): rotation period 35.5±0.1 hours with a brightness amplitude of 0.22±0.02 mag. Quality code of 2+. Summary figures at the LCDB
    2. [b]
      With the stress on the first syllable.

    References

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