K2-16 c
K2-16 c is a mini-Neptune orbiting the K3 V star K2-16 in the constellation Virgo. It lies about 1,093 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is K2-16 c?
K2-16 c has a radius of 2.54 times that of Earth.
Is K2-16 c in the Habitable Zone?
K2-16 c orbits inside the inner edge of the habitable zone of K2-16. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-16: 0.352–0.861 AU (conservative: 0.446–0.816 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-16 c
The equilibrium temperature of K2-16 c is about 485 K (212 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 13.10 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-16 c — one full orbit around K2-16 — lasts 19.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.123 AU — closer to its star than Mercury is to the Sun.
How Was K2-16 c Discovered?
K2-16 c was discovered in 2015 using the transit method, with observations from K2.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is K2-16 c?
K2-16 c is 1,092.5 light-years (335.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,093 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 19,228,000 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. K2-16 c scores 0.33, ranking #918 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-16
K2-16
- Spectral type
- K3 V
- Surface temperature
- 4,742 K (Sun: 5,772 K)
- Mass
- 0.68 M☉
- Radius
- 0.66 R☉
The K2-16 Planetary System
K2-16 c is one of 3 known planets in the K2-16 system. Its siblings:
- EPIC 201754305 d (Terrestrial)
- K2-16 b (Mini Neptune)
K2-16 c — Complete Data
| Radius | 2.540 Earth radii (0.227 Jupiter radii) |
|---|---|
| Orbital period | 19.08 days |
| Orbital distance | 0.123 AU |
| Equilibrium temperature | 485 K (212 °C) |
| Stellar irradiation | 13.10× Earth |
| Earth Similarity Index | 0.33 |
| Distance from Earth | 1,092.5 light-years (335.0 parsecs) |
| Constellation | Virgo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2016-07-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-16 c
Is K2-16 c habitable?
No — K2-16 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-16 c?
K2-16 c is about 1,093 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 19,228,000 years to get there.
How big is K2-16 c compared to Earth?
K2-16 c has 2.54 times the radius of Earth.
How long is a year on K2-16 c?
One orbit around K2-16 takes 19.1 Earth days — short enough that 19 of its years would fit into one Earth year.
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