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Orbital diagram | |
| Discovery | |
|---|---|
| Discovered by | Johann Palisa |
| Discovery date | 10 December 1879 |
| Designations | |
| (211) Isolda | |
| Pronunciation | /ɪˈzoʊldə/[1] |
Named after | Iseult |
| A879 XA, 1912 AB 1912 BA, 1950 FM | |
| Main belt | |
| Adjectives | Isoldian /ɪˈzoʊldiən/[2] |
| Orbital characteristics[3] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 136.19 yr (49742 d) |
| Aphelion | 3.53270 AU (528.484 Gm) |
| Perihelion | 2.5514 AU (381.68 Gm) |
| 3.04205 AU (455.084 Gm) | |
| Eccentricity | 0.16129 |
| 5.31 yr (1938.0 d) | |
Average orbital speed | 17.08 km/s |
| 260.142° | |
| 0° 11m 8.74s / day | |
| Inclination | 3.8856° |
| 263.644° | |
| 173.522° | |
| Physical characteristics | |
| Dimensions | 143.19±5.1 km[3] 149.81 ± 6.10 km[4] |
| Mass | (4.49 ± 2.43) × 1018 kg[4] |
Mean density | 2.54 ± 1.41 g/cm3[4] |
| 18.365 h (0.7652 d) | |
| 0.0602±0.004[3] 0.0598 ± 0.0218[5] | |
| C[5] (Tholen) | |
| 7.89,[3] 7.90[5] | |
211 Isolda is a very large, dark main-belt asteroid. It is classified as a C-type asteroid and is probably composed of primitive carbonaceous material. The spectra of the asteroid displays evidence of aqueous alteration.[6]
It was discovered by Austrian astronomer Johann Palisa on 10 December 1879, in Pola, and is possibly named after Isolde, heroine of the legend of Tristan and Iseult.[7]
In 2001, the asteroid was detected by radar from the Arecibo Observatory at a distance of 1.78 AU. The resulting data yielded an effective diameter of 143 ± 16 km.[8]
Between 2009 and 2022, 211 Isolda has been observed to occult seven stars.[citation needed]