Exoplanet · Earth-sized rocky planet
HD 101581 b
HD 101581 b is a Earth-sized rocky planet orbiting the star HIP 56998. Its year lasts 4.47 Earth days. It was discovered in 2025 by the Transit method.
| Host star | HIP 56998 |
|---|---|
| Distance | 41.7 light-years (12.8 pc) |
| Orbital period | 4.47 days |
| Orbital radius | 0.046 AU |
| Radius | 0.956 R⊕ · 0.0853 R♃ |
| Mass | 0.827 M⊕ · 0.0026 M♃ (estimated from the radius) |
| Density | 5.2 g/cm³ |
| Equilibrium temperature | 834 K (561 °C) |
| Stellar flux received | 80 × Earth |
| Discovery method | Transit |
| Discovery year | 2025 |
| Discovered by | Transiting Exoplanet Survey Satellite (TESS) |
Habitable zone
Inside the inner edge of the habitable zone: it receives 80 times the light the Earth does, too hot to keep liquid water on its surface.
Its star in the sky
In the planet's sky its star is a disc 7.3° across: 14 times the Sun as we see it from Earth.
In the sky
Too faint for the naked eye (magnitude 7.77); binoculars will find it. Visible from the whole Southern Hemisphere and north to latitude 46° N. South of latitude 46° S it never sets. It stands highest at midnight in March, the best time to observe it.
Light's journey
The light you see tonight set out around the year 1984. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 739 thousand years.
Planets in the same system
- HD 101581 c 6.2-day orbit · 0.99 R⊕
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.