|Discovered by||Michael E. Brown, |
David Rabinowitz, et al.
|Discovery date||30 June 2005|
|(136108) 2003 EL61 II|
S/2005 (2003 EL61) 2
|Epoch JD 2454615.0|
|Eccentricity||0.249±0.015 (in 2009; variable)|
13.41°±0.08° relative to Hiʻiaka (in 2008; variable)
|~85 km (if albedo is same as primary's 0.7±0.1)|
|Mass||1.79 ± 1.48×1018 kg |
(0.05% the mass of Haumea)
|(assumed to be near 1 g/cm3)|
|21.9 (4.6 difference from primary's 17.3)|
Namaka is only 1.5% as bright as its parent dwarf planet Haumea and is about 0.05% its mass. If it turns out to have a similar albedo, it would be about 170 km in diameter. Photometric observations indicate that its surface is made of water ice. Mutual events between 2009 and 2011 were expected to improve the knowledge of the orbits and masses of the components of the Haumean system, but interpreting those observations was greatly complicated by the unexpected non-tidally locked spin state of Hiʻiaka, the larger moon. 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.