Hi'iaka (moon)

Infobox Planet
name = Hiokinaiaka
bgcolour = #a0ffa0


caption = An artist's impresion of Haumea and its moons Namaka and Hiʻiaka.
discovery = yes
discoverer = Michael E. Brown,
Chad Trujillo,
David Rabinowitz, "et al."
discovered = 2005 January 26
alt_names = Haumea I
adjectives = Hiokinaiakan
orbit_ref = cite web|url=http://www.johnstonsarchive.net/astro/astmoons/am-136108.html|author=Wm. Robert Johnston |title=(136108) Haumea, Hi'iaka, and Namaka |updated=17 September 2008 |accessed=17 September 2008 ]
semimajor = 49 500 ± 400 km
eccentricity = 0.050 ± 0.003
period = 49.12 ± 0.03 days
inclination = 234.8 ± 0.3°
satellite_of = dp|Haumea
physical_characteristics = yes
mean_radius = ~155 km
mass = ~4e|20 kg
density = (unknown; close to 1 if water ice)
single_temperature = 32 ± 3 K
rotation = (unknown)
axial_tilt = (unknown)
albedo = (unknown)
magnitude = 3.3 difference from primary's 17.3

Hiokinaiaka (pron-en|ˌhiːʔiːˈɑːkə respell|HEE|’ee|AH|kə, or as in Hawaiian IPAlink|ˈhiʔiˈjɐkə), also known as Haumea I, is the larger, outer moon of the dwarf planet Haumea. Its provisional designation was S/2005 (mp|2003 EL|61) 1.

Discovery and Naming

Hiokinaiaka was the first satellite discovered around Haumea. It is named after one of the daughters of Haumea, Hiokinaiaka, the patron goddess of the Big Island of Hawaii, though at first it had gone by the nickname "Rudolph" by its discovery team. It orbits once every 49.12 ± 0.03 days at a distance of 49,500 ± 400 km, with an eccentricity of 0.050 ± 0.003 and an inclination of 234.8 ± 0.3°. Mutual occultations occurred in 1999 and will not occur again until 2138.

ize and Brightness

Measured brightness is 5.9 ± 0.5% translating into the diameter about 22% of its primary, or in the range of 350 km, assuming similar albedo. To put this in perspective, this moon would be the fifth largest asteroid after 1 Ceres, 2 Pallas, 4 Vesta, and 10 Hygiea if it were in the asteroid belt, as it can be seen in the list of largest known asteroids out to the orbit of Jupiter.

Mass

Only the total mass of the system is known, but assuming the moon has the same density and albedo as the primary, their magnitude difference (3.3) can be used to estimate the mass of the satellite as 1% of the mass of Haumea.

References

External links

* [http://www.gps.caltech.edu/%7Embrown/papers/ps/EL61.pdf Brown's publication describing the discovery of Hiokinaiaka]
* [http://www.gps.caltech.edu/~mbrown/papers/ps/rudolph.pdf Paper describing the composition of Hiokinaiaka]