Kepler-539 c
Kepler-539 c is a cold gas giant orbiting the G2 V star Kepler-539 in the constellation Cygnus. It lies about 1,002 light-years from Earth and was discovered in 2016 using the transit timing variations method.
Is Kepler-539 c in the Habitable Zone?
Kepler-539 c orbits beyond the outer edge of the habitable zone of Kepler-539. At that distance, any surface water would almost certainly be frozen.
Habitable zone of Kepler-539: 0.723–1.702 AU (conservative: 0.916–1.613 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Kepler-539 c
The equilibrium temperature of Kepler-539 c is about 253 K (-20 °C) — in a range broadly comparable to Earth, whose equilibrium temperature is 255 K. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on Kepler-539 c — one full orbit around Kepler-539 — lasts 1,000.0 Earth days, longer than an Earth year. It orbits at an average distance of 2.420 AU. Its orbit is highly elliptical (eccentricity 0.50), swinging dramatically closer to and farther from its star.
How Was Kepler-539 c Discovered?
Kepler-539 c was discovered in 2016 using the transit timing variations method, with observations from Kepler.
Transit timing variations reveal a planet through its gravitational tug on a sibling planet, which makes that sibling's transits arrive slightly early or late. The pattern of these deviations betrays the hidden planet's mass and orbit.
How Far Away Is Kepler-539 c?
Kepler-539 c is 1,002.3 light-years (307.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1024. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 17,640,480 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. Kepler-539 c scores 0.20, ranking #3,840 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-539
Kepler-539
- Spectral type
- G2 V
- Surface temperature
- 5,820 K (Sun: 5,772 K)
- Mass
- 1.05 M☉
- Radius
- 0.95 R☉
The Kepler-539 Planetary System
Kepler-539 c is one of 2 known planets in the Kepler-539 system. Its siblings:
- Kepler-539 b (Cold Gas Giant)
Kepler-539 c — Complete Data
| Mass | 762.79 Earth masses (2.400 Jupiter masses) |
|---|---|
| Orbital period | 1,000.00 days |
| Orbital distance | 2.420 AU |
| Eccentricity | 0.500 |
| Equilibrium temperature | 253 K (-20 °C) |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 1,002.3 light-years (307.3 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit Timing Variations |
| Discovery facility | Kepler |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2016-05-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-539 c
Is Kepler-539 c habitable?
No — Kepler-539 c orbits outside the habitable zone of Kepler-539 and is likely too cold for liquid water on its surface.
How far away is Kepler-539 c?
Kepler-539 c is about 1,002 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 17,640,480 years to get there.
How long is a year on Kepler-539 c?
One orbit around Kepler-539 takes 1,000.0 Earth days.
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