Namaka (moon)
( 13.41 ± 0.08 ° to Hi'iaka ) °
Team of the Keck Observatory
Namaka is the inner and smaller moon of the dwarf planet Haumea Plutoiden and cubewanos. Its average diameter is about 160 kilometers, which corresponds to about 1/10 of the (average) diameter of Haumea.
Discovery and designation
Namaka was on 30 June 2005 by a team consisting of Michael E. Brown, MA van Dam, AH Bouchez, D. Le Mignant, RD Campbell, JCY Chin, A. Conrad, SK Hartman, EM Johansson, RE Lafon, David Lincoln Rabinowitz, PJ Stomski, Jr., DM Summers, Chadwick A. Trujillo, and PL Wizinowich with observations at Keck Observatory on Mauna Kea in Hawaii discovered. The name was provisionally suggested by the discovery team Blitzer. Blitzer is the name of the reindeer of Santa Claus. The discovery was announced on 29 November 2005; the moon was given the provisional designation S/2005 (2003 EL61 ) 2
On 17 September 2008 the moon was named after Namaka, the Hawaiian water spirit, which is to be born, in contrast to its sister Hiiaka from the body of Haumea.
Web properties
The companion orbits Haumea in a prograde, very elliptical orbit 19268-32046 km Distance to the center ( large semi-major axis estimated 25,657 km or 23 Haumea equatorial radii ). The orbital eccentricity is 0.249, the orbit is inclined 113.013 ° to the ecliptic.
The orbital eccentricity is highly unusual, as the Mondysteme in the solar system with distance are usually eccentric to the central body. Namaka also has the most eccentric in relation to its proximity to the central body orbit, caused probably due to disturbances due to resonances with the outer moon Hi'iaka. It is believed that both moons wander through the tidal forces outwards. Currently they are located approximately in a 8:3 resonance. Thus the orbit of Namaka is disturbed, which currently has a precession of ~ 20 °. In addition, the orbit is tilted with respect to the second moon Hiiaka to about 13 °.
Namaka orbits Haumea in 18 days 6 hours and 40.8 minutes, resulting in a Haumea - year corresponds to approximately 5660.7 rounds (about 283.28 Earth years ).
At the time you see the Haumea system from Earth about from the side, so that Namaka Haumea covered periodically. This is useful to determine the shape and mass of Haumea by the slight changes in brightness precisely.
Physical Properties
Namaka has a diameter estimated at 160 km, based on the assumed albedo of 8%. The surface is so very dark, the moon is 4.6 / - 0.5 may fainter than Haumea. Its density is estimated to be as Hi'iaka 1.0 ± 0.5 g/cm3. Strong absorption at wavelengths of 1.2 and 2 microns in the infrared spectrum indicates that the surface is mainly composed of water ice. The average surface temperature of Namaka is estimated at -241 ° C (32 K).
The mass of Namaka is not precisely known, but assuming the same density and albedo as Haumea, a mass yields of about 0.2 % of that of the central body.
It is possible that Namaka has arisen from material of an impact of another body in Haumea.