Object profile · HAUMEA
Haumea
Dwarf planet · Kuiper Belt · Ringed
A rapidly rotating, elongated ice world with two moons and the first ring found around a dwarf planet.
- Atlas data reviewed
- Editorial stage
- Published
- Visibility
- Public
Artist visualizationArtist visualization, not a resolved spacecraft image. Shape and ring are scientifically constrained; color and texture are interpretive.
Vastward original reconstruction; scientific basis: NASA Science and Ortiz et al. (2017) ↗What this world is
Haumea spins once in under four hours. That speed stretches it into an elongated shape; a ring and two moons make it a whole miniature system rather than a simple isolated rock.
Why it looks this way now
No spacecraft has visited Haumea. Shape, ring, rotation and surface composition come from coordinated telescopes and models.
Where it sits
Haumea follows an inclined orbit beyond Neptune in the Kuiper Belt and belongs to a family of fragments with similar icy surfaces.
Swipe sideways to inspect the full map
Haumea orbits the Sun directly at a mean distance of about 43.1 AU; the marker is not a live position.
Neptune provides the outer-planet reference. The shaded zone shows the broad relationship to the Kuiper Belt, while muted dots are other profiled outer-system dwarf planets; horizontal distance is heavily compressed.
Read the numbers
Reference values retain their units, context, evidence state and published uncertainty.
Physical measurements
- Mean radiusglobal mean
- 798.0kmScientific modelSmaller than Earth's Moon.
A volume-equivalent radius for a strongly elongated body.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Massglobal mean
- 4.006E21kgCalculated measurementFar below Earth's mass, yet enough gravity to become rounded.
Calculated from the motion of a spacecraft, moon or dynamical system.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Mean densityglobal mean
- 1.885g/cm³Scientific modelA clue to the relative mixture of rock, water ice and voids.
Density is calculated from mass and volume; it does not reveal a unique interior by itself.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Reference gravitysurface
- 0.42m/s²Scientific modelOnly a few percent of Earth's surface gravity.
Gravity varies strongly across the elongated, rapidly rotating surface.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Temperaturesurface
- -241°CScientific modelCold enough for volatile compounds to remain as surface ice.
A model-supported representative temperature, not a thermometer reading on the ground.
Approximate value
Representative equilibrium or surface temperature; local and seasonal conditions vary.
Orbit and rotation
- Average distancerelative to the Sun
- 43.100AUCalculated measurementDozens of times farther from the Sun than Earth.
The semi-major-axis reference summarizes an orbit whose actual distance changes.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Rotation periodrelative to distant stars
- 3.9154hCalculated measurementOne of the fastest rotations among large Solar System bodies.
A sidereal rotation period relative to distant stars.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
- Orbital periodrelative to the Sun
- 282.00Earth yearsCalculated measurementOne full season cycle lasts many human lifetimes.
Calculated from long-baseline astrometry and a fitted heliocentric orbit.
No uncertainty published in this source table
The selected summary source does not publish a compact uncertainty for this reference value.
Atmosphere and inside
Atmosphere
No persistent atmosphere has been detected. At this distance, volatile materials are expected to remain frozen on or within the surface.
Surface and interior
Water ice covers a relatively dense body. Its exact three-dimensional shape and internal distribution remain model-dependent.
- 1Rock-rich interior model
Its mass and modeled volume imply a relatively dense interior, but exact shape and density remain under revision.
Scientific model - 2Water-ice-rich surface
Spectra reveal crystalline water ice coating much of the rapidly rotating body.
Scientific model - 3Narrow ring system
A stellar occultation revealed a ring; the artwork shows its existence and orientation schematically.
Scientific model
How we know
Size comes from imaging, thermal data or occultation; orbit and rotation from repeated positions and brightness; mass only when gravity leaves a measurable trace.
- 01Calculated measurement
Stellar-occultation shape reconstruction
Multiple observatories time the object's shadow crossing a background star to reconstruct chords across its silhouette.
Where this method stops
A single event samples one orientation and requires a shape model.
- 02Calculated measurement
Gravity from orbital motion
The motion of a moon or spacecraft reveals the central body's gravitational parameter.
Where this method stops
The solution depends on orbit coverage and a dynamical model.
- 03Calculated measurement
Thermal radiometry and spectroscopy
Brightness at visible, infrared and thermal wavelengths constrains temperature, reflectivity and surface ices.
Where this method stops
Temperature and size can trade off against albedo, roughness and thermal assumptions.
- 04Calculated measurement
Long-baseline astrometry
Repeated sky positions over years are fitted to a heliocentric orbit.
Where this method stops
Long-period distant objects need many years of observations and future values remain predictions.
- 05Calculated measurement
Rotational light curve
Repeating brightness changes reveal a candidate rotation period.
Where this method stops
Shape, surface markings and viewing angle can create aliases or double-peaked solutions.
Evidence key
- Direct observation
- An instrument or sample recorded the phenomenon, with processing still disclosed.
- Calculated measurement
- Observed motion or signal is converted into a physical quantity using equations and reference constants.
- Scientific model
- A tested interpretation that fits observations but is not directly imaged or sampled.
- Vastward explanation
- Original beginner-facing synthesis, traceable to the source records but not itself a measurement.
- Artist visualization
- An interpretive image, not observational evidence.
Missions and instruments
Hubble Space Telescope
Hubble observations help resolve Haumea's moons, brightness and system context from Earth orbit.
Official mission ↗- Hubble WFC3Resolved imaging and brightness of the Haumea system.
Official source trail
Links below are the exact records used for this profile. Access dates are retained with the content.
- 01
NASA Science · official-page
Haumea Facts
- Source updated
- No source update date published
- Access checked
- 2026-07-31
- 02
NASA Jet Propulsion Laboratory, Solar System Dynamics · dataset
JPL Small-Body Database Lookup: 136108 Haumea
- Source updated
- No source update date published
- Access checked
- 2026-07-31
- 03
Nature · research-paper
The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation
- Source updated
- 2017-10-11
- Access checked
- 2026-07-31
- 04
NASA Science · official-page
Hubble Space Telescope
- Source updated
- No source update date published
- Access checked
- 2026-07-31
Continue exploring
Atlas is a starting point. Use these relationships to move into explanation, experiment and mission thinking.
Why is it a dwarf planet?
Use Haumea to separate roundness, orbit and orbital clearing—the three ideas behind the classification.
academyCompare the small worlds
Place radius, density and sunlight side by side without pretending every value is equally certain.
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