103 Hera

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103 Hera
Discovery
Discovered by James Craig Watson[1]
Discovery date September 7, 1868[1]
Designations
Named after Hera
Alternative names 1927 CV, 1950 CM
Minor planet category Main belt
Orbital characteristics[2]
Epoch August 27, 2011 (JD 2455800.5)[1]
Aphelion 437.17 Gm (2.9223 AU)[1]
Perihelion 371.24 Gm (2.4816 AU)[1]
Semi-major axis 404.202 Gm (2.702 AU)[1]
Eccentricity 0.0815455[1]
Orbital period 1622.213 d (4.4414 a)[1]
Average orbital speed 18.09 km/s
Mean anomaly 74.835°
Inclination 5.421°
Longitude of ascending node 136.276°
Argument of perihelion 190.160°
Physical characteristics
Dimensions 91.2 km
Mass 7.9×1017 kg
Equatorial surface gravity 0.0255 m/s²
Escape velocity 0.0482 km/s
Rotation period 0.9892[3] d
Temperature ~170 K
Spectral type S[4]
Absolute magnitude (H) 7.66

    103 Hera is a moderately large main-belt asteroid that was discovered by Canadian-American astronomer James Craig Watson on September 7, 1868,[5] and named after Hera, queen and fifth in power of the Olympian gods in Greek mythology. It is an S-type asteroid[4] with a silicate surface composition.

    Photometric observations made in 2010 at the Organ Mesa Observatory at Las Cruces, New Mexico, and the Hunters Hill Observatory at Ngunnawal, Australian Capital Territory, give a synodic rotation period of 23.740 ± 0.001 hours. The bimodal light curve shows a maximum brightness variation of 0.45 ± 0.03 in magnitude.[3]

    Measurements made with the IRAS observatory give a diameter of 91.58 ± 4.14 km and a geometric albedo of 0.19 ± 0.02. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 88.30 ± 8.51 km and a geometric albedo of 0.20 ± 0.04. When the asteroid was observed occulting a star, the results showed a diameter of 89.1 ± 1.1 km.[6]

    References

    1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 JPL Small-Body Database Browser
    2. Yeomans, Donald K., "103 Hera", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-25. 
    3. 3.0 3.1 Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 38 (1): 32, Bibcode:2011MPBu...38...32P. 
    4. 4.0 4.1 DeMeo, Francesca E. et al. (2011), "An extension of the Bus asteroid taxonomy into the near-infrared", Icarus 202 (1): 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, retrieved 2013-03-22.  See appendix A.
    5. "Numbered Minor Planets 1–5000", Discovery Circumstances (IAU Minor Planet center), retrieved 2013-04-07. 
    6. Ryan, Erin Lee et al. (April 2012), "The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer", eprint arXiv, arXiv:1204.1116, Bibcode:2012arXiv1204.1116R. 


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