Ilmarë
Hubble Space Telescope image of Varda and its satellite Ilmarë, taken in 2010 and 2011 | |
| Discovery | |
|---|---|
| Discovered by | Keith S. Noll et al. |
| Discovery date | 2009, based on images taken on 26 April 2009 |
| Designations | |
Designation | Varda I |
| Pronunciation | /ˈɪlməriː/ |
Named after | Ilmarë (figure by J. R. R. Tolkien) |
| (174567) Varda I | |
| Adjectives | Ilmarëan /ɪlməˈriːən/ |
| Orbital characteristics | |
| 4805±35 km or 4812±35 km | |
| Eccentricity | 0.0181±0.0045 or 0.0247±0.0048 (0.0215±0.0080 adopted) |
| 5.75058±0.00015 d | |
| Inclination | 101.0±1.9 or 85.1±1.8 |
| Satellite of | Varda |
| Physical characteristics | |
| 403±40 km | |
| Mass | ≈2.2×1019 kg |
Mean density | 1.24+0.50 −0.35 g/cm3 (system) |
| Albedo | 0.068±0.011 (2025) ≈0.085 (2020) |
Spectral type | B−V = 0.857±0.061 V−I = 1.266±0.052 |
| Varda + 1.7 | |
Ilmarë, formal designation (174567) Varda I, is the only known moon of the large Kuiper belt object 174567 Varda. It was discovered by Keith Noll et al. in 2009, at a separation of about 0.12 arcsec, using discovery images taken by the Hubble Space Telescope on 26 April 2009, and reported in 2011. At approximately 403 km in diameter (about 45% that of its primary), it is the fourth-largest known moon of a trans-Neptunian object, after Pluto I Charon, Eris I Dysnomia, and Orcus I Vanth. Assuming that Ilmarë has the same albedo and density as Varda, Ilmarë would constitute approximately 8.4% of the system's mass, approximately 2.2×1019 kg.