Actaea (moon)

Actaea
Salacia and its moon Actaea, imaged by the Keck telescope on 3 August 2010. Actaea is the fainter object to the left of Salacia.
Discovery
Discovered byKeith S. Noll, Harold F. Levison, Denise C. Stephen, William M. Grundy
Discovery date21 July 2006
Designations
Designation
Salacia I
Pronunciation/ækˈtə/
S/2006 (120347) 1
AdjectivesActaean /ækˈtən/
Orbital characteristics
5700+30
−29
km
Eccentricity0.008±0.003
5.49389±0.00001 days
Inclination17.2±0.5°
108.9±1.6°
41+33
−22
°
Satellite ofSalacia
Physical characteristics
393±33 km
Mass20×1018 kg
Mean density
~0.63 g/cm3 (calculated)
5.49389±0.00001 d (synchronous)
Albedo0.021±0.004
Spectral type
V–I = 0.89±0.02
6.850±0.053

Actaea, formal designation (120347) Salacia I, is the only known moon of the classical Kuiper belt object 120347 Salacia. Its diameter is estimated to be 393 km (244 mi), which is approximately one-half the diameter of Salacia; thus, Salacia and Actaea are viewed by William Grundy et al. to be a binary system. Assuming that the following size estimates are correct, Actaea is about the fifth-biggest known moon of a trans-Neptunian object, after Charon (1212 km), Dysnomia (615 km), Vanth (443 km), and Ilmarë (403 km).