Here we report Wide-Field Planetary Camera 2 observations of the Quaoar-Weywot Kuiper Belt binary. From these observations, we find that Weywot is on an elliptical orbit with an eccentricity of 0.14 ± 0.04, a period of 12.438 ± 0.005 days, and a semimajor axis of 1.45 ± 0.08 × 104 km. The orbit reveals a surprisingly high-Quaoar-Weywot system mass of (1.6 ± 0.3) × 1021 kg. Using the surface properties of the Uranian and Neptunian satellites as a proxy for Quaoar's surface, we reanalyze the size estimate from Brown & Trujillo. We find, from a mean of available published size estimates, a diameter for Quaoar of 890 ± 70 km. We find Quaoar's density to be ρ = 4.2 ± 1.3gcm-3, possibly the highest density in the Kuiper Belt.
The Astrophysical Journal
- Pub Date:
- May 2010
- Kuiper Belt: general;
- Kuiper Belt objects: individual: Quaoar;
- Astrophysics - Earth and Planetary Astrophysics
- 11 pages, 2 figures, accepted for publication in ApJ letters.