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Exoplanet · mini-Neptune

Kepler-123 b

Kepler-123 b is a mini-Neptune orbiting the star Kepler-123. Its year lasts 17.2 Earth days. It was discovered in 2014 by the Transit method.

Host starKepler-123
Distance3,332 light-years (1,022 pc)
Orbital period17.2 days
Orbital radius0.135 AU
Eccentricity0.000
Radius2.94 R⊕ · 0.262 R♃
Mass55.3 M⊕ · 0.174 M♃
Density12 g/cm³
Surface gravity6.4 × Earth
Equilibrium temperature817 K (544 °C)
Stellar flux received139 × Earth
Discovery methodTransit
Discovery year2014
Discovered byKepler

Habitable zone

Inside the inner edge of the habitable zone: it receives 139 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 5° across: 9.4 times the Sun as we see it from Earth.

In the sky

A telescope is needed to see it: its apparent magnitude is 14.13. Visible from the whole Northern Hemisphere and south to latitude 47° S. North of latitude 47° N it never sets. It stands highest at midnight in July, the best time to observe it.

Light's journey

The light you see tonight set out around 1307 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 59 million years.

Planets in the same system

Open in the simulation

Data: NASA Exoplanet Archive, PSCompPars. Its look in the simulation is a rendering based on the measured radius, mass and temperature.