Discovery | |
---|---|
Discovered by | P. P. Henry, 1877 |
Discovery date | 5 November 1877 |
Designations | |
(177) Irma | |
Main belt | |
Orbital characteristics[1] | |
Epoch 31 July 2016 (JD 2457600.5) | |
Uncertainty parameter 0 | |
Observation arc | 115.30 yr (42113 d) |
Aphelion | 3.4260 AU (512.52 Gm) |
Perihelion | 2.1110 AU (315.80 Gm) |
2.7685 AU (414.16 Gm) | |
Eccentricity | 0.23749 |
4.61 yr (1682.5 d) | |
42.096° | |
0° 12m 50.256s / day | |
Inclination | 1.3893° |
347.55° | |
38.184° | |
Earth MOID | 1.11401 AU (166.654 Gm) |
Jupiter MOID | 2.03001 AU (303.685 Gm) |
TJupiter | 3.296 |
Physical characteristics | |
Mean radius | 36.61±0.8 km |
13.856 h (0.5773 d)[1][2] | |
0.0527±0.002 | |
C | |
9.49 | |
Irma (minor planet designation: 177 Irma) is a fairly large and dark main belt asteroid. It was discovered by the French brothers Paul Henry and Prosper Henry on November 5, 1877. Paul was cred for this discovery. The meaning of the name Irma is unknown.[3]
Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico in 2011 gave a light curve with a period of 13.856 ± 0.001 hours and a brightness variation of 0.30 ± 0.03 in magnitude.[2]