225 Henrietta

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225 Henrietta
Discovery
Discovered by Johann Palisa
Discovery date April 19, 1882
Designations
Alternative names n/a
Minor planet category Main belt (Cybele)
Orbital characteristics
Epoch 30 January 2005 (JD 2453400.5)
Aphelion 641.471 Gm (4.288 AU)
Perihelion 370.46 Gm (2.476 AU)
Semi-major axis 505.966 Gm (3.382 AU)
Eccentricity 0.268
Orbital period 2271.87 d (6.22 a)
Average orbital speed 16.2 km/s
Mean anomaly 215.046°
Inclination 20.902°
Longitude of ascending node 197.199°
Argument of perihelion 104.697°
Physical characteristics
Dimensions 121.0 km
Mass unknown
Mean density unknown
Equatorial surface gravity unknown
Escape velocity unknown
Rotation period 7.356 h
Albedo .040
Temperature unknown
Spectral type C
Absolute magnitude (H) 8.72

    225 Henrietta is a very large outer main-belt asteroid. It was discovered by Johann Palisa on April 19, 1882, in Vienna and named after Henrietta, wife of astronomer Pierre J. C. Janssen.

    This is classified as a C-type asteroid and is probably composed of privitive carbonaceous material. It has very dark surface, with an albedo of 0.040. Photometric measurements made from the Oakley Southern Sky Observatory during 2012 gave a light curve with a period of 7.352 ± 0.003 hours and a variation in brightness of 0.18 ± 0.02 in magnitude. This is consistent with a synodic rotation period of 7.356 ± 0.001 hours determined in 2000.[1]

    225 Henrietta belongs to Cybele group of asteroids and is probably in a 4:7 orbital resonance with the planet Jupiter.

    References

    1. Moravec, Patricia; Cochren, Joseph; Gerhardt, Michael et al. (October 2012), "Asteroid Lightcurve Analysis at the Oakley Southern Sky Observatory: 2012 January-April", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 39 (4): 213–216, Bibcode:2012MPBu...39..213M. 
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