13point8All planet systems
3 known planets · 1,957 light years

PSR B1257+12

PSR B1257+12 is a star 1,957 light years away, with 3 confirmed planets. Distances and orbital speeds are to scale; the star and planets are enlarged so you can see them.

Day 0
habitable zone (estimate)planet orbits

Green band: where liquid water could exist on a planet's surface. Drag to turn the system, pinch or scroll to zoom.

The star

The star

PSR B1257+12

Type
star
Mass
1.40 × the Sun

The planets

PSR B1257+12

PSR B1257+12 b

Year
25.26 days
Distance from star
0.19 AU
Mass
0.02 Earths
Size
0.34 × Earth
Found
1994, pulsar timing (Arecibo Observatory)
Outside the habitable zone
PSR B1257+12

PSR B1257+12 c

Year
66.54 days
Distance from star
0.36 AU
Mass
4.3 Earths
Size
1.9 × Earth
Found
1992, pulsar timing (Arecibo Observatory)
Outside the habitable zone
PSR B1257+12

PSR B1257+12 d

Year
98.21 days
Distance from star
0.46 AU
Mass
3.9 Earths
Size
1.8 × Earth
Found
1992, pulsar timing (Arecibo Observatory)
Outside the habitable zone

Masses found by the wobble method are minimums, because the orbit's tilt is unknown. Temperatures are equilibrium estimates for a bare planet, before any atmosphere.

How we know

Pulsar Timing

Discovered by pulsar timing.

Sources

  1. Planet and star parameters: NASA Exoplanet Archive, Planetary Systems Composite Parameters, retrieved 1 Nov 2026. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.
  2. Position: HYG Database v4.1 (CC BY-SA 4.0).
  3. Habitable zone: a simple estimate from the star's brightness (√L × 0.95 to 1.67 AU), shown as a guide.
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