Exoplanet · mini-Neptune
HD 180617 b
HD 180617 b is a mini-Neptune orbiting the star HD 180617. Its year lasts 106 Earth days. It was discovered in 2018 by the Radial Velocity method.
| Host star | HD 180617 |
|---|---|
| Distance | 19.3 light-years (5.91 pc) |
| Orbital period | 106 days |
| Orbital radius | 0.343 AU |
| Eccentricity | 0.101 |
| Radius | 3.53 R⊕ · 0.315 R♃ |
| Mass (minimum) | 12.2 M⊕ · 0.0384 M♃ |
| Density | 1.53 g/cm³ |
| Equilibrium temperature | 202 K (-71 °C) |
| Stellar flux received | 0.275 × Earth |
| Discovery method | Radial Velocity |
| Discovery year | 2018 |
| Discovered by | Calar Alto Observatory |
Habitable zone
Beyond the habitable zone: it receives only %28 of the light the Earth does, a frozen world.
Its star in the sky
In the planet's sky its star is a disc 0.75° across: 1.4 times the Sun as we see it from Earth.
In the sky
A telescope is needed to see it: its apparent magnitude is 9.12. Visible from the whole Northern Hemisphere and south to latitude 85° S. It stands highest at midnight in July, the best time to observe it.
Light's journey
The light you see tonight set out around the year 2007. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 342 thousand years.
Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.