CoRoT-18 b
CoRoT-18 b is a hot Jupiter orbiting the G9 V star CoRoT-18 in the constellation Monoceros. It lies about 2,495 light-years from Earth and was discovered in 2011 using the transit method.
How Big Is CoRoT-18 b?
CoRoT-18 b has a radius of 14.68 times that of Earth, or 1.31 times the radius of Jupiter. Its mass is 1,103 times that of Earth, giving it a density of 2.20 g/cm³ — between that of rocky and gaseous planets.
Is CoRoT-18 b in the Habitable Zone?
CoRoT-18 b orbits inside the inner edge of the habitable zone of CoRoT-18. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of CoRoT-18: 0.679–1.615 AU (conservative: 0.859–1.531 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on CoRoT-18 b
The equilibrium temperature of CoRoT-18 b is about 1,550 K (1,277 °C) — hot enough to melt many metals. 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 CoRoT-18 b — one full orbit around CoRoT-18 — lasts just 45.6 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.030 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.08).
How Was CoRoT-18 b Discovered?
CoRoT-18 b was discovered in 2011 using the transit method, with observations from CoRoT.
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 CoRoT-18 b?
CoRoT-18 b is 2,494.7 light-years (764.9 parsecs) from Earth. Light arriving here tonight left the planet about 2,495 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 43,906,720 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. CoRoT-18 b scores 0.06, ranking #5,101 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: CoRoT-18
CoRoT-18
- Spectral type
- G9 V
- Surface temperature
- 5,440 K (Sun: 5,772 K)
- Mass
- 0.95 M☉
- Radius
- 1.00 R☉
Planetary System
CoRoT-18 b is the only planet known to orbit CoRoT-18 so far.
CoRoT-18 b — Complete Data
| Radius | 14.680 Earth radii (1.310 Jupiter radii) |
|---|---|
| Mass | 1,102.82 Earth masses (3.470 Jupiter masses) |
| Density | 2.20 g/cm³ (Earth: 5.51) |
| Orbital period | 1.90 days |
| Orbital distance | 0.030 AU |
| Eccentricity | 0.080 |
| Equilibrium temperature | 1,550 K (1,277 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 2,494.7 light-years (764.9 parsecs) |
| Constellation | Monoceros |
| Discovery method | Transit |
| Discovery facility | CoRoT |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2019-12-02. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About CoRoT-18 b
Is CoRoT-18 b habitable?
No — CoRoT-18 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is CoRoT-18 b?
CoRoT-18 b is about 2,495 light-years from Earth in the constellation Monoceros. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 43,906,720 years to get there.
How big is CoRoT-18 b compared to Earth?
CoRoT-18 b has 14.68 times the radius of Earth and about 1,103 times its mass.
How long is a year on CoRoT-18 b?
One orbit around CoRoT-18 takes 1.9 Earth days — short enough that 192 of its years would fit into one Earth year.
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