Ilmarë

Ilmarë,^[b] or Varda I, full designation 174567 Varda I Ilmarë, is the single known natural satellite of the 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.^[4] At approximately 326 km in diameter (about 45% that of its primary), it is the fourth or fifth-largest known moon of a trans-Neptunian object, after Pluto I Charon, Eris I Dysnomia, Orcus I Vanth and very possibly Haumea I Hiʻiaka. 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.

Name

Names for Varda and its moon were announced on 2014 January 16. Ilmarë (Quenya: [ˈilmarɛ]) is a chief of the Maiar and handmaiden to Varda, the queen of the Valar, creator of the stars, and principal goddess of the elves in J. R. R. Tolkien's fictional mythology.^[1]

Characteristics

Ilmarë and Varda are tightly bound, with a separation of about 13 Varda radii, and a consequently low angular momentum. Along with the high inclination of Varda's orbit, they are similar in this way to the Orcus–Vanth and Salacia–Actaea systems. As of 2015 two mirror orbital solutions are possible with slightly different orbital parameters. The calculated eccentricity is inconsistent with the likely age of the system, suggesting that it might be spurious, but the expected age is also contradicted by suggestions that Varda may not be tidally locked.^[2]

If Ilmarë and Varda have the same albedo, Ilmarë would be 163+19
−17 km in radius, or approximately 8.4% the volume of Varda. If the two bodies also have the same density, Ilmarë would then have approximately 8.4% the system mass of (2.664±0.064)×10²⁰ kg. If, however, the albedo of Varda is 50% greater than that of Ilmarë, Ilmarë would have a radius of 191+22
−21 km and the bulk density of the system would be 1.31+0.52
−0.36 g/cm³. If Ilmarë has a 50%-greater albedo, then its radius would be 137+16
−15 km and the bulk density would be 1.18+0.47
−0.33 g/cm³. Because the absolute magnitudes of the two bodies at different wavelengths are similar, it's not likely that their albedos differ by much, so Ilmarë is likely to be in this size range.^[2]

Notes

References

• v
• t
• e

Dwarf planets

• List of possible dwarf planets
• Former dwarf planets
  • Phoebe
  • Triton
  • Vesta
  • Pallas
• Mesoplanet
• Planemo

Consensus

• Ceres
  • Geology
  • Atmosphere
• Orcus
  • Moon
• Pluto
  • Geology
  • Atmosphere
  • Moons
• Haumea
  • Moons
  • Ring
• Makemake
  • Moon
• Quaoar
  • Moon
  • Rings
• Eris
  • Moon
• Gonggong
  • Moon
• Sedna

Possible

Asteroid belt	Hygiea Interamnia
Centaurs	Chariklo Chiron Pholus 1999 OX3 2013 TC146 2014 NW65
Plutinos	Huya Ixion 2001 QF298 2002 VR128 2002 XV93 2003 AZ84 2003 UZ413 2003 VS2 2007 JH43 2017 OF69
Twotinos	2002 WC19
Cubewanos	Chaos Salacia Varda Varuna 1998 SN165 2002 AW197 2002 CY248 2002 KX14 2002 MS4 2002 UX25 2003 QW90 2004 GV9 2004 NT33 2004 PF115 2004 TY364 2004 UX10 2005 RN43 2005 UQ513 2010 FX86
Other KBOs	1999 CD158 1999 DE9 2000 YW134 2002 XW93 2010 JO179 2010 VK201 2011 FW62 2011 GM27 2013 FZ27 2014 UM33 2015 AM281 2015 RR245
Scattered disc	Gǃkúnǁʼhòmdímà Dziewanna 1996 GQ21 1996 TL66 2001 UR163 2002 TC302 2004 XA192 2005 QU182 2005 RM43 2006 QH181 2008 OG19 2010 KZ39 2010 RE64 2010 RF43 2010 JO179 2010 TJ 2010 VZ98 2013 FY27 2014 AN55 2014 EZ51 2014 UZ224 2014 WK509 2015 KH162 2015 RR245 2017 FO161 2018 AG37 2018 VG18 2021 DR15 2021 LL37
Detached objects	2003 FY128 2003 QX113 2004 XR190 2005 TB190 2007 JJ43 2008 ST291
Sednoids	2012 VP113

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