Hi'iaka (moon)

( 13.41 ± 0.08 ° to Namaka ) °

Team of the Keck Observatory

Hiiaka is the outer and larger moon of the dwarf planet Haumea Plutoiden and cubewanos. Its average diameter is about 310 kilometers, which corresponds to approximately 1/ 5 of the (average) diameter of Haumea.

Discovery and designation

Hiiaka was discovered on 28 January 2005 by a team with observations from January 26 to 30 at the Keck Observatory on Mauna Kea in Hawaii. The name was provisionally proposed by Rudolph discovery team, the name of the most famous reindeer of Santa Claus in a popular American Christmas song. The moon was given the provisional designation S/2005 (2003 EL61 ) 1

On 17 September 2008 the moon was named after Hiiaka, the Hawaiian goddess that is to be born from the mouth of Haumea. Hi'iaka is the goddess of dance and patron of the Big Island of Hawaii.

Web properties

The companion orbits Haumea in a prograde, slightly elliptical orbit 47321-52439 km Distance to the center ( large semi-major axis estimated 49,880 km or 45 Haumea equatorial radii ). The orbital eccentricity is 0.0513, the orbit is inclined 126.356 ° to the ecliptic. In addition, the circulation path is compared with the second moon Namaka tilted by about 13 ° ( 40 ° previous calculations ).

Hi'iaka is probably responsible for the unusually high eccentricity of the inner moon Namaka, which is caused by interference due to resonances. Currently they are located approximately in a 8:3 resonance. It is believed that both moons wander through the tidal forces outwards.

Hi'iaka orbits Haumea in 49 days 11 hours and 5.3 minutes, which in a Haumea - year corresponds to approximately 2091.9 rounds (about 283.28 Earth years ).

Physical Properties

Hiiaka has a diameter estimated at 320 km, based on the assumed albedo of 8%. The surface is so very dark. Their density is estimated to be as Namaka 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 Hiiaka today is estimated at 1.79 ∙ 1019 kg, assuming the same density and albedo as Haumea, so a mass of about 0.45 percent of those of the central body.

It is possible that Hiiaka originated from material of an impact of another body in Haumea.

Research

In 1999, seen from Earth, a cover of the moon through its central body, this will happen again until the year 2138.