174567 Varda

Varda
Discovery[1]
Discovered by J. A. Larsen[2]
Discovery date 21 June 2003
Designations
MPC designation (174567) Varda
2003 MW12
TNO (cubewano)[3]
SCATEXTD[4]
Orbital characteristics[1]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc 12837 days (35.15 yr)
Aphelion 52.212 AU (7.8108 Tm)
Perihelion 39.399 AU (5.8940 Tm)
45.805 AU (6.8523 Tm)
Eccentricity 0.13986
310.02 yr (113233 d)
4.37 km/s
266.990°
0.0031793°/day
Inclination 21.495°
183.943°
182.916°
Known satellites 1
Earth MOID 38.3965 AU (5.74403 Tm)
Jupiter MOID 34.4405 AU (5.15223 Tm)
Physical characteristics
Dimensions 705+81
−75 km (primary)
361+42
−38 km (satellite)[5]
722+82
−76 km (primary)
326+38
−34 km (satellite)[6]
Mass (2.664±0.064)×1020 kg[6]
Mean density
 1.24+0.50
−0.35 g/cm3[5][lower-alpha 1]
5.91 h (0.246 d)
5.61 h[6]
0.102+0.024
−0.024[5]
0.166+0.043
−0.033[6]
Temperature ≈ 41 K
B−V=0.892±0.028
V−I=1.133±0.034 (Varda)
B−V=0.857±0.061
V−I=1.266±0.052 (Ilmarë)[6]
20.5[7]
3.61 ± 0.05[5]
3.097 ± 0.060[6]
3.4[1]

    174567 Varda /ˈvɑːrdə/ (Quenya: [ˈvarda]), provisional designation 2003 MW12, is a trans-Neptunian object with an absolute magnitude of 3.5.[1] It is highly likely to be a dwarf planet.[8]

    Discovery and orbit

    174567 Varda was discovered in March, 2006, using imagery dated from June 21, 2003 by Jeffrey A. Larsen with the Spacewatch telescope as part of a United States Naval Academy Trident Scholar project.[9]

    It is currently 47.5 AU from the Sun,[7] and will come to perihelion around November 2096.[4][10] It has been observed 68 times over 14 oppositions with precovery images back to 1980.[1]

    Name

    Names for Varda and its moon were announced on 16 January 2014. Varda is the queen of the Valar, creator of the stars, and principal goddess of the elves in J.R.R. Tolkien's fictional mythology. Ilmarë is a chief of the Maiar and Varda's handmaiden.[11]

    Satellite

    Varda has at least one satellite, Ilmarë /ˈɪlməriː/ (stress on the first syllable, Quenya: [ˈilmarɛ]), or Varda I, which was discovered in an image obtained by the Hubble Space Telescope on 26 April 2009, and reported in 2011. It is estimated to be about 320–360 km in diameter (about 50% that of its primary). As of 2015 two mirror orbital solutions are possible with slightly different parameters.[5][6]

    Orbital parameters of the Varda–Ilmarë system[6]
    Semi-major axis (km) Eccentricity Period (d) Inclination (°)
    4809 ± 39 0.0215 ± 0.0080 5.75058 ± 0.00015 82–100

    Physical properties

    The estimated combined size of the Varda–Ilmarë system is 792+91
    −84     km    . The size of the primary is estimated at 705+81
    −75     km    . The total mass of the system is about 2.66×1020 kg. The density of both the primary and the satellite is estimated at about 1.24 g/cm3 assuming that they have equal density.[5][6]

    The surfaces of both the primary and the satellite appear to be red in the visible and near-infrared parts of the spectrum (spectral class IR), with Ilmarë being slightly redder than Varda. The spectrum of the system does not show water absorption but shows evidence of methanol ice. The rotation period of Varda is estimated at 5.61 hours.[6]

    Notes

    1. ↑ Assuming Varda and Ilmarë have equal albedos and equal densities

    References

    1. 1 2 3 4 5 "JPL Small-Body Database Browser: 174567 (2003 MW12)" (2007-06-14 last obs). Retrieved 25 March 2016.
    2. ↑ "List Of Transneptunian Objects". Minor Planet Center. Retrieved 26 August 2016.
    3. ↑ "MPEC 2009-P26 :Distant Minor Planets (2009 AUG. 17.0 TT)". Minor Planet Center. 2009-08-07. Retrieved 2009-08-24.
    4. 1 2 Marc W. Buie (2008-04-15). "Orbit Fit and Astrometric record for 174567". SwRI (Space Science Department). Retrieved 2009-08-24.
    5. 1 2 3 4 5 6 Vilenius, E.; Kiss, C.; Mommert, M.; et al. (2014). ""TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations". Astronomy & Astrophysics. 564: A35. arXiv:1403.6309Freely accessible. Bibcode:2012A&A...541A..94V. doi:10.1051/0004-6361/201322416.
    6. 1 2 3 4 5 6 7 8 9 10 W.M. Grundy; S.B. Porter; S.D. Benecchi; et al. (2015). "The mutual orbit, mass, and density of the large transneptunian binary system Varda and Ilmarë". Icarus. 257: 130–138. arXiv:1505.00510Freely accessible. Bibcode:2015Icar..257..130G. doi:10.1016/j.icarus.2015.04.036.
    7. 1 2 "AstDys (174567) 2003MW12 Ephemerides". Department of Mathematics, University of Pisa, Italy. Archived from the original on 2009-04-18. Retrieved 2009-03-22.
    8. ↑ Michael E. Brown. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Retrieved 16 September 2016.
    9. ↑ Larsen, Jeffrey A.; Roe, Eric A.; Albert, C. Elise; et al. (2007). "The Search for Distant Objects in the Solar System Using Spacewatch". The Astronomical Journal. 133 (4): 1247–1270. Bibcode:2007AJ....133.1247L. doi:10.1086/511155.
    10. ↑ "HORIZONS Web-Interface". JPL Solar System Dynamics. Retrieved 2009-08-24.
    11. ↑ M.P.C. 86285, 2014 Jan. 16, p. 431

    External links

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