Discovered by Johann Palisa Alternative names n/a Observation arc 120.87 yr (44148 d) Orbits Sun Discoverer Johann Palisa Asteroid group Cybele asteroid | Discovery date 19 April 1882 Minor planet category Main belt (Cybele) Discovered 19 April 1882 Spectral type C-type asteroid Discovery site Vienna Observatory | |
Aphelion 4.28364 AU (640.823 Gm) Similar 266 Aline, 276 Adelheid, 220 Stephania, 192 Nausikaa, 230 Athamantis | ||
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.
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.
225 Henrietta belongs to Cybele group of asteroids and is probably in a 4:7 orbital resonance with the planet Jupiter.