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Namaka (moon)

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Namaka
In this photo taken by the Hubble Space Telescope, Namaka is the faint spot near the bottom, directly below Haumea (center).
Discovery
Discovered byMichael E. Brown,
Chad Trujillo,
David Rabinowitz, et al.
Discovery date30 June 2005
Designations
Designation
Haumea II
Pronunciation/nɑːˈmɑːkə/
Hawaiian: [naːˈmɐkə]
(136108) 2003 EL61 II
S/2005 (2003 EL61) 2
Orbital characteristics[1]
Epoch JD 2454615.0
25657±91 km[1]
Eccentricity0.249±0.015 (in 2009; variable)
18.2783±0.0076 d[1]
178.5°±1.7°
Inclination113.013°±0.075°
13.41°±0.08° relative to Hiʻiaka (in 2008; variable)
205.016°±0.228°
178.9°±2.3°
Satellite ofHaumea
Physical characteristics
~85 km (if albedo is same as primary's 0.7±0.1)
Mass(1.79±1.48)×1018 kg[1]
(0.05% the mass of Haumea)
Mean density
(assumed to be near 1 g/cm3)
?
Albedo0.8±0.2[2][3]
Temperature32±3 K
21.9 (4.6 difference from primary's 17.3)[2]

Namaka is the smaller, inner moon of the trans-Neptunian dwarf planet Haumea. Discovered in 2005, it is named after Nāmaka, the goddess of the sea in Hawaiian mythology and one of the daughters of Haumea. Namaka is notable for its unusual, highly-perturbed orbit that is heavily influenced by the larger, outer moon Hi'iaka.

Discovery

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Namaka was discovered on 30 June 2005 and announced on 29 November 2005.[4] It was nicknamed "Blitzen" by the discovery team before being assigned an official name.[citation needed]

Physical characteristics

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Namaka is only 1.5% as bright as its parent dwarf planet Haumea[5] and is about 0.05% its mass. If it turns out to have a similar albedo, it would be about 170 km in diameter.[2] Photometric observations indicate that its surface is made of water ice.[5] Mutual events between 2009 and 2011[6] were expected to improve the knowledge of the orbits and masses of the components of the Haumean system,[3] but interpreting those observations was greatly complicated by the unexpected non-tidally locked spin state of Hiʻiaka, the larger moon. Namaka is similar in size to Makemake's moon MK2, despite being smaller. Further observations of Hiʻiaka might allow to determine its rotation period and spin state more precisely, at which point it should be possible to remove its effect from the data obtained in 2009.[7][8]

See also

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References

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  1. ^ a b c d Ragozzine, D.; Brown, M. E. (2009). "Orbits and Masses of the Satellites of the Dwarf Planet Haumea (2003 EL61)". The Astronomical Journal. 137 (6): 4766–4776. arXiv:0903.4213. Bibcode:2009AJ....137.4766R. doi:10.1088/0004-6256/137/6/4766. S2CID 15310444.
  2. ^ a b c Wm. Robert Johnston (17 September 2008). "(136108) Haumea, Hi'iaka, and Nāmaka". Archived from the original on 21 December 2017. Retrieved 18 September 2008.
  3. ^ a b Ragozzine, D.; Brown, M. E. (2009). "Orbits and Masses of the Satellites of the Dwarf Planet Haumea (2003 EL61)". The Astronomical Journal. 137 (6): 4766–4776. arXiv:0903.4213. Bibcode:2009AJ....137.4766R. doi:10.1088/0004-6256/137/6/4766. S2CID 15310444.
  4. ^ Green, Daniel W. E. (1 December 2005). "IAUC 8636". Archived from the original on 26 December 2017. Retrieved 14 November 2018.
  5. ^ a b Barkume, K. M.; Brown, M. E.; Schaller, E. L. (2006). "Water Ice on the Satellite of Kuiper Belt Object 2003 EL61" (PDF). The Astrophysical Journal. 640 (1): L87–L89. arXiv:astro-ph/0601534. Bibcode:2006ApJ...640L..87B. doi:10.1086/503159. S2CID 17831967. Archived (PDF) from the original on 12 February 2012. Retrieved 18 September 2008.
  6. ^ Brown, M. "Mutual events of Haumea and Namaka". Archived from the original on 24 February 2009. Retrieved 18 February 2009.
  7. ^ Hastings, Danielle M; Ragozzine, Darin; Fabrycky, Daniel C; Burkhart, Luke D; Fuentes, Cesar; Margot, Jean-Luc; Brown, Michael E; Holman, Matthew (2016). "The Short Rotation Period of Hiʻiaka, Haumea's Largest Satellite". The Astronomical Journal. 152 (6): 195. arXiv:1610.04305. Bibcode:2016AJ....152..195H. doi:10.3847/0004-6256/152/6/195. S2CID 33292771.
  8. ^ Grundy, W. M; Benecchi, S. D; Rabinowitz, D. L; Porter, S. B; Wasserman, L. H; Skiff, B. A; Noll, K. S; Verbiscer, A. J; Buie, M. W; Tourtellotte, S. W; Stephens, D. C; Levison, H. F (2012). "Mutual Events in the Cold Classical Transneptunian Binary System Sila and Nunam". Icarus. 220 (1): 74–83. arXiv:1204.3923. Bibcode:2012Icar..220...74G. doi:10.1016/j.icarus.2012.04.014. S2CID 16784376.
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