16974 Iphthime
| Hubble Space Telescope image of Iphthime taken in 2013 | |
| Discovery | |
|---|---|
| Discovered by | LINEAR | 
| Discovery site | Lincoln Lab's ETS | 
| Discovery date | 18 November 1998 | 
| Designations | |
| (16974) Iphthime | |
| Pronunciation | /ɪfˈθaɪmiː/ | 
| Named after | Iphthime Iphthīmē/Ἰφθῑμη (Greek mythology) | 
| 1998 WR21 · 1974 WX 1986 WS | |
| Jupiter trojan Greek · background | |
| Adjectives | Iphthimean | 
| Orbital characteristics | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 42.86 yr (15,655 d) | 
| Aphelion | 5.5556 AU | 
| Perihelion | 4.8248 AU | 
| 5.1902 AU | |
| Eccentricity | 0.0704 | 
| 11.82 yr (4,319 d) | |
| 261.74° | |
| 0° 5m 0.24s / day | |
| Inclination | 15.036° | 
| 241.56° | |
| 134.72° | |
| Jupiter MOID | 0.0605 AU | 
| TJupiter | 2.9270 | 
| Physical characteristics | |
| 55.43±4.0 km 57.15±3.85 km 57.34±0.33 km | |
| 78.9±0.4 h | |
| 0.065±0.010 0.066±0.009 0.0691±0.011 | |
| C (assumed) V–I = 0.960±0.035 | |
| 9.80 | |
16974 Iphthime (/ɪfˈθaɪmiː/; provisional designation 1998 WR21) is a Jupiter trojan and a binary system from the Greek camp, approximately 57 kilometers (35 miles) in diameter. It was discovered on 18 November 1998, by astronomers with the Lincoln Near-Earth Asteroid Research at the ETS Test Site in Socorro, New Mexico. The dark Jovian asteroid belongs to the 80 largest Jupiter trojans and has a notably slow rotation of 78.9 hours. It was named after Iphthime from Greek mythology. The discovery of its companion by Hubble Space Telescope was announced in March 2016.