225 Henrietta
Main-belt asteroid
From Wikipedia, the free encyclopedia
225 Henrietta is a very large outer main-belt asteroid. It was discovered by Austrian astronomer Johann Palisa on April 19, 1882, in Vienna and named after Henrietta, wife of astronomer Pierre J. C. Janssen.[2] The asteroid is orbiting at a distance of 3.39 AU from the Sun with a period of 6.24 years and an eccentricity (ovalness) of 0.26. The orbital plane is inclined at an angle of 20.9° to the plane of the ecliptic.[1] 225 Henrietta belongs to Cybele group of asteroids.[3]
Lightcurve-base 3D-model of 225 Henrietta. | |
| Discovery | |
|---|---|
| Discovered by | Johann Palisa |
| Discovery date | 19 April 1882 |
| Designations | |
| (225) Henrietta | |
| Pronunciation | /hÉnriËÉtÉ/ |
Named after | Henrietta Jansen |
| A882 HA | |
| Main belt (Cybele) | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 120.87 yr (44,148 d) |
| Aphelion | 4.28364 AU (640.823 Gm) |
| Perihelion | 2.4945 AU (373.17 Gm) |
| 3.38907 AU (506.998 Gm) | |
| Eccentricity | 0.26396 |
| 6.24 yr (2,278.9 d) | |
Average orbital speed | 16.2 km/s |
| 159.155° | |
| 0° 9m 28.703s / day | |
| Inclination | 20.872° |
| 197.113° | |
| 104.149° | |
| Physical characteristics | |
| Dimensions | 120.49±2.5 km |
| 7.3556 h (0.30648 d) | |
| 0.0396±0.002 | |
| C | |
| 8.72 | |
This is classified as a C-type asteroid and is probably composed of primitive carbonaceous material. It has a 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 h 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 h determined in 2000.[4] In 2001, the asteroid was detected by radar from the Arecibo Observatory at a distance of 1.58 AU. The resulting data yielded an effective diameter of 128±16 km.[5]
