174567 Varda
174567 Varda (provisional designation 2003 MW12) is a binary trans-Neptunian planetoid of the resonant hot classical population of the Kuiper belt, located in the outermost region of the Solar System. Its moon, Ilmarë, was discovered in 2009.
Hubble Space Telescope image of Varda and its satellite Ilmarë, taken in 2010 and 2011 | |
| Discovery | |
|---|---|
| Discovered by | J. A. Larsen |
| Discovery site | Kitt Peak National Obs. |
| Discovery date | 21 June 2003 |
| Designations | |
Designation | (174567) Varda |
| Pronunciation | /ˈvɑːrdə/ |
Named after | Varda (figure by J. R. R. Tolkien) |
Alternative names | 2003 MW12 |
Minor planet category | TNO · cubewano detached · distant |
| Symbol | (astrological) |
| Orbital characteristics | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 39.12 yr (14,290 d) |
| Earliest precovery date | 19 March 1980 |
| Aphelion | 52.711 AU |
| Perihelion | 39.510 AU |
Semi-major axis | 46.110 AU |
| Eccentricity | 0.14315 |
Orbital period (sidereal) | 313.12 yr (114,366 d) |
Mean anomaly | 275.208° |
Mean motion | 0° 0m 11.332s / day |
| Inclination | 21.511° |
Longitude of ascending node | 184.151° |
| ≈ 1 November 2096 ±4 days | |
| 180.072° | |
| Known satellites | 1 (Ilmarë) |
| Physical characteristics | |
Mean diameter | 740±14 km (area equivalent) 722+82 −76 km |
| Flattening | 0.080±0.049 (for period of 11.82 h) or 0.235±0.050 (for period of 5.91 h) |
| Mass | (2.45±0.06)×1020 kg |
Mean density | 1.23±0.04 g/cm3 (for period of 11.82 h) 1.78±0.06 g/cm3 (for period of 5.61 h) |
Synodic rotation period | 5.61 h or 5.91 h (single-peaked) 11.82 h (double-peaked) |
| Albedo | 0.099±0.002 (primary) 0.102+0.024 −0.024 |
Spectral type | IR (moderately red) B−V=0.886±0.025 V–R=0.55±0.02 V−I=1.156±0.029 |
| 20.5 | |
| 3.81±0.01 (primary) 3.097±0.060 3.4 | |
Astronomer Michael Brown estimates that, with an absolute magnitude of 3.5 and a calculated diameter of approximately 700–800 kilometers (430–500 miles), it is likely a dwarf planet. However, William M. Grundy et al. argue that objects in the size range of 400–1000 km, with albedos less than ≈0.2 and densities of ≈1.2 g/cm3 or less, have likely never compressed into fully solid bodies, let alone differentiated, and so are highly unlikely to be dwarf planets. It is not clear if Varda has a low or a high density.