13point8All planet systems
1 known planet · 3,901 light years

V0391 Peg

V0391 Peg is a hot star (sdBV) 3,901 light years away, with 1 confirmed planet. 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

V0391 Peg

Type
sdBV
Surface
≈ 29,300 K
Size
0.23 × the Sun
Mass
0.50 × the Sun
Brightness
27.1 × the Sun
Habitable zone
4.94–8.69 AU

The planets

V0391 Peg

V0391 Peg b

Year
3.2 years
Distance from star
1.7 AU
Mass
at least 3.2 Jupiters
Size
13 × Earth
Temperature
≈ 520 K (+247 °C)
Found
2007, pulsation timing variations (Multiple Observatories)
Too hot

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

Pulsation Timing Variations

Discovered by pulsation timing variations.

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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