Kepler-553 c
Kepler-553 c is a cold gas giant orbiting Kepler-553 in the constellation Cygnus. It lies about 2,376 light-years from Earth and was discovered in 2016 using the transit method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
How Big Is Kepler-553 c?
Kepler-553 c has a radius of 11.58 times that of Earth, or 1.03 times the radius of Jupiter. Its mass is 2,129 times that of Earth, giving it a density of 7.53 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is Kepler-553 c in the Habitable Zone?
Kepler-553 c orbits inside the conservative habitable zone of Kepler-553 — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of Kepler-553: 0.568–1.363 AU (conservative: 0.719–1.293 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Temperature on Kepler-553 c
The equilibrium temperature of Kepler-553 c is about 251 K (-22 °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. It receives 0.59 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Kepler-553 c — one full orbit around Kepler-553 — lasts 328.2 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.898 AU — comparable to the inner Solar System. Its orbit is highly elliptical (eccentricity 0.35), swinging dramatically closer to and farther from its star.
How Was Kepler-553 c Discovered?
Kepler-553 c was discovered in 2016 using the transit method, with observations from Kepler.
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 Kepler-553 c?
Kepler-553 c is 2,376.1 light-years (728.5 parsecs) from Earth. Light arriving here tonight left the planet about 2,376 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 41,819,360 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-553 c scores 0.39, ranking #513 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Kepler-553
Kepler-553
- Surface temperature
- 5,191 K (Sun: 5,772 K)
- Mass
- 0.89 M☉
- Radius
- 0.90 R☉
- Luminosity
- 0.5360 L☉
- Age
- 8.8 billion years (Sun: 4.6)
The Kepler-553 Planetary System
Kepler-553 c is one of 2 known planets in the Kepler-553 system. Its siblings:
- Kepler-553 b (Neptune-like)
Kepler-553 c — Complete Data
| Radius | 11.579 Earth radii (1.033 Jupiter radii) |
|---|---|
| Mass | 2,129.45 Earth masses (6.700 Jupiter masses) |
| Density | 7.53 g/cm³ (Earth: 5.51) |
| Orbital period | 328.24 days |
| Orbital distance | 0.898 AU |
| Eccentricity | 0.346 |
| Equilibrium temperature | 251 K (-22 °C) |
| Stellar irradiation | 0.59× Earth |
| Earth Similarity Index | 0.39 |
| Distance from Earth | 2,376.1 light-years (728.5 parsecs) |
| Constellation | Cygnus |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2016 |
Data: NASA Exoplanet Archive, last updated 2024-09-13. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Kepler-553 c
Is Kepler-553 c habitable?
Kepler-553 c orbits within the habitable zone of Kepler-553, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is Kepler-553 c?
Kepler-553 c is about 2,376 light-years from Earth in the constellation Cygnus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 41,819,360 years to get there.
How big is Kepler-553 c compared to Earth?
Kepler-553 c has 11.58 times the radius of Earth and about 2,129 times its mass.
How long is a year on Kepler-553 c?
One orbit around Kepler-553 takes 328.2 Earth days.
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