Haumea

• Region: Kuiper Belt
  
  

• Diameter: ~1,960 × 1,518 × 996 km (ellipsoidal)
  
  

• Mass: 4 × 10²¹ kg
  
  

• Orbit: 284 Earth years, semi-major axis ~43.1 AU, eccentricity 0.19
  
  

• Rotation: 3.9 hours (very rapid)
  
  

Surface & Geology:
Haumea has a highly elongated shape due to rapid rotation. The surface is covered mainly by crystalline water ice, making it highly reflective. There are no clear impact craters visible, suggesting either a resurfacing process or ice flow smoothing the terrain. Its rapid spin likely prevents a fully spherical shape.

Moons & Rings:

• Hiʻiaka and Namaka: Small moons orbiting Haumea.
  
  

• Ring system: Thin ring discovered in 2017, aligned with Haumea’s equatorial plane.
  
  

Internal Structure:
Models suggest a dense rocky core with an ice mantle. Its high density (~2.6 g/cm³) indicates a significant rock fraction. Past collisions likely shaped its current spin and elongated form.

Temperature:
Surface temperatures ~–241°C, extremely cold and stable.

Discovery:
Discovered in 2004 by Mike Brown’s team. The fast rotation and moons were confirmed in subsequent observations.