From Handwiki - Reading time: 3 min| Discovery | |
|---|---|
| Discovered by | G. Van Biesbroeck |
| Discovery site | Williams Bay |
| Discovery date | 23 November 1922 |
| Designations | |
| (990) Yerkes | |
| Pronunciation | /ˈjɜːrkiːz/ |
| 1922 MZ | |
| Orbital characteristics[1] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 102.46 yr (37425 days) |
| |{{{apsis}}}|helion}} | 3.2477 astronomical unit|AU (485.85 Gm) |
| |{{{apsis}}}|helion}} | 2.0916 AU (312.90 Gm) |
| 2.6696 AU (399.37 Gm) | |
| Eccentricity | 0.21652 |
| Orbital period | 4.36 yr (1593.2 d) |
| Mean anomaly | 216.84° |
| Mean motion | 0° 13m 33.456s / day |
| Inclination | 8.7872° |
| Longitude of ascending node | 353.971° |
| 9.4832° | |
| Physical characteristics | |
| Mean radius | 9.23±0.6 km |
| Rotation period | 24.56 h (1.023 d) |
| Sidereal rotation period | 24.45 ± 0.05[2] h |
| Geometric albedo | 0.1303±0.018 |
| Absolute magnitude (H) | 11.7 |
990 Yerkes is a main belt asteroid discovered by Belgian-American astronomer George Van Biesbroeck in 1922, and named after the Yerkes Observatory.
Photometric observations of this asteroid collected during 2009 show a rotation period of 24.45 ± 0.05 hours with a brightness variation of 0.35 ± 0.05 magnitude.[2]