WASP-12 b

WASP-12 b

Planet· orbits the Sun

WASP-12 b — a hot Jupiter (~1.47 Jupiter masses, 1.97 Jupiter radii) being DEVOURED by its star. Orbiting in just 26 hours, it is so close that tides have stretched it into an egg / rugby-ball shape and are stripping gas from it; it is also one of the darkest planets known, reflecting almost no light. Its orbit is measurably decaying — it is spiralling inward to destruction. Its density (real from transit + mass) reflects how grotesquely inflated it has become. Never imaged directly.

Open in 3D viewSee WASP-12 b in the live, interactive 3D map

Key facts

Mass
2.79 × 10²⁷ kg
1.47 M♃ (467 M⊕)
Radius
140,325 km
22× wider than Earth
Surface gravity
9.46 m/s²
96% of Earth's
Year
1.09 Earth days
Distance from WASP-12
3,500,590 km

Science

Physical

Mass
2.79 × 10²⁷ kg · 1.47 M♃ (467 M⊕)
Radius
140,325 km · 22× wider than Earth
Density
241 kg/m³ · 0.24× water
Surface gravity
9.46 m/s² · 96% of Earth's
Escape velocity
51.5 km/s · 4.61× Earth's

Orbital

Semi-major axis
3,500,590 km
Eccentricity
0
Inclination
0.00 °
Orbital period
26.19 hours
Perihelion
3,500,590 km
Aphelion
3,500,590 km
Mean orbital velocity
233 km/s

Composition

Bulk composition
A hot Jupiter of ~1.47 Jupiter masses and 1.97 Jupiter radii; because it transits with a measured mass, its very low density is real, reflecting how grotesquely inflated it has become. Tides have stretched it into a rugby-ball shape and strip gas from it; it is also one of the darkest planets known, reflecting almost no light. Transit-timing shows its orbit decaying by milliseconds a year — it is spiralling inward to destruction. Never imaged directly.
Cloud appearance
Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The banded clouds shown are a representation of its class, shown only in Vision mode; Realism shows a plain spectral colour.

Radiation & temperature

Insolation
7,240 S⊕ · 7,240× the sunlight Earth receives
Equilibrium temperature
2,601 K (2328 °C)

Discovery & history

Method
Transit detection
Name
Designated 'b' under the IAU convention that letters a star's planets 'b', 'c', 'd'... in the order they are found (the star is the unwritten 'a'); no IAU proper name has been assigned.

Discovered transiting by the WASP survey in 2008. Follow-up revealed it losing mass to its star and, from transit-timing, an orbit shrinking by milliseconds per year — direct evidence the planet is being consumed and will not survive.

Images

Artist's impression of WASP-12 b — a pitch-black hot Jupiter being devoured and stretched by its star — an artist's concept, not a photograph.
NASA, ESA, and G. Bacon (STScI) — CC BY 4.0 · Wikimedia Commons
Artist's concept of the hot Jupiter WASP-12 b, among the hottest known planets — an artist's impression, not a photograph.
NASA/JPL-Caltech (public domain) · Wikimedia Commons

Images from open archives · credit shown per image