| Ymir | |
| Discovery Ref: | [1] |
| Discoverer: | Brett J. Gladman |
| Discovery Site: | Observatoire de la Cote d'Azur |
| Discovered: | 2000 |
| Alt Names: | S/2000 S 1 |
| Mpc Name: | Saturn XIX |
| Pronounced: | , [2] |
| Adjective: | Ymirian [3] |
| Named After: | Ymir |
| Orbit Ref: | [4] |
| Epoch: | 2000 January 1.5 |
| Eccentricity: | 0.337 |
| Period: | −3.6 yr (−1315.16 d) |
| Inclination: | 173.1° |
| Mean Anomaly: | 344.3° |
| Arg Peri: | 90.8° |
| Asc Node: | 61.5° |
| Satellite Of: | Saturn |
| Group: | Norse group |
| Physical Ref: | [5] [6] |
| Circumference: | 65 km (equatorial) |
| Albedo: | 0.06 |
| Spectral Type: | D/P |
| Magnitude: | 21.7 |
| Abs Magnitude: | 12.3 |
Ymir, or Saturn XIX, is the second-largest retrograde irregular moon of Saturn. It was discovered by Brett J. Gladman, et al. in 2000, and given the temporary designation S/2000 S 1. It was named in August 2003 after Ymir, who in Norse mythology is the ancestor of all the Jotuns or frost giants.[7]
It takes 3.6 Earth years to complete an orbit around Saturn. Of the moons that take more than 3 Earth years to orbit Saturn, Ymir is the largest, at about 19km (12miles) in diameter;[8] Ymir is also the second largest member of the Norse group, after Phoebe.[9]
Spectral measurements from Cassini–Huygens show that Ymir is reddish in color, unlike Phoebe's gray color, suggesting a separate origin for this moon. It shows a similar light curve as Siarnaq and has a triangular shape, rotating in a retrograde direction about once every 11.9 hours.[9]