PSR B1257+12 b
Planet· orbits PSR B1257+12
PSR B1257+12 b ('Draugr') — an astonishingly tiny world, only about twice the Moon's mass (0.02 M⊕): one of the least massive exoplanets known. It circles the pulsar every 25 days, a fragment of a world drowned in radiation. Mass from timing; no density is quoted.
Open in 3D viewSee PSR B1257+12 b in the live, interactive 3D map
Key facts
Minimum mass
1.19 × 10²³ kg
0.02 M⊕
Year
25.26 Earth days
Distance from PSR B1257+12
0.19 AU
Science
Physical
- Minimum mass (m·sin i)
- 1.19 × 10²³ kg · 0.02 M⊕
- Radial-velocity detection measures m·sin i; the true mass depends on the unknown orbital inclination.
- Radius
- Not measured
- Found by pulsar timing: the mass is a timing minimum and the ~0.34 R⊕ size is a model estimate, so no density is quoted.
Orbital
- Semi-major axis
- 0.19 AU
- From the NASA Exoplanet Archive (pulsar-timing solution)
- Eccentricity
- 0
- From the NASA Exoplanet Archive (pulsar-timing solution)
- Inclination
- 0.00 °
- From the NASA Exoplanet Archive (pulsar-timing solution)
- Orbital period
- 25.3 days
- From the NASA Exoplanet Archive (pulsar-timing solution)
- Perihelion
- 0.19 AU
- Computed from the orbital elements
- Aphelion
- 0.19 AU
- Computed from the orbital elements
- Mean orbital velocity
- 81.8 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A tiny world of only ~0.02 Earth masses (about twice the Moon's), circling a dead star every 25 days, scoured by pulsar radiation. Nature unknown; nothing has been imaged.
- Surface appearance
- Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The surface shown is an artistic representation, shown only in Visual mode; Realism shows a plain spectral colour.
Discovery & history
- Method
- Pulsar-timing detection
- Name
- Designated 'b' under the IAU planet-lettering convention; no IAU proper name has been assigned. (Historically also labelled A, B, C.)
Found in 1994, refining the 1992 discovery — the smallest of the three pulsar planets.
Images
Never imaged — this world is known only from the split-second shifts it causes in its pulsar's radio beat. An artist's concept of the whole system is on the system view; no image of the planet itself exists.