Exoplanet · mini-Neptune
TOI-139 b
TOI-139 b is a mini-Neptune orbiting the star TOI-139. Its year lasts 11.1 Earth days. It was discovered in 2023 by the Transit method.
| Host star | TOI-139 |
|---|---|
| Distance | 138.3 light-years (42.4 pc) |
| Orbital period | 11.1 days |
| Radius | 2.46 R⊕ · 0.219 R♃ |
| Mass | 6.6 M⊕ · 0.0208 M♃ (estimated from the radius) |
| Density | 2.45 g/cm³ |
| Equilibrium temperature | 561 K (288 °C) |
| Stellar flux received | 22.4 × Earth |
| Discovery method | Transit |
| Discovery year | 2023 |
| Discovered by | Transiting Exoplanet Survey Satellite (TESS) |
Habitable zone
Inside the inner edge of the habitable zone: it receives 22.4 times the light the Earth does, too hot to keep liquid water on its surface.
In the sky
A telescope is needed to see it: its apparent magnitude is 10.55. Visible from the whole Southern Hemisphere and north to latitude 55° N. South of latitude 55° S it never sets. It stands highest at midnight in August, the best time to observe it.
Light's journey
The light you see tonight set out around the year 1888. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 2.5 million years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.