CoRoT-9 b
CoRoT-9 b is a cold gas giant orbiting CoRoT-9 in the constellation Serpens. It lies about 1,347 light-years from Earth and was discovered in 2009 using the transit method.
How Big Is CoRoT-9 b?
CoRoT-9 b has a radius of 11.95 times that of Earth, or 1.07 times the radius of Jupiter. Its mass is 267 times that of Earth, giving it a density of 0.86 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is CoRoT-9 b in the Habitable Zone?
CoRoT-9 b orbits inside the inner edge of the habitable zone of CoRoT-9. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of CoRoT-9: 0.689–1.630 AU (conservative: 0.873–1.546 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on CoRoT-9 b
The equilibrium temperature of CoRoT-9 b is about 420 K (147 °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.
Orbit and Year Length
A year on CoRoT-9 b — one full orbit around CoRoT-9 — lasts 95.3 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.402 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.13).
How Was CoRoT-9 b Discovered?
CoRoT-9 b was discovered in 2009 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-9 b?
CoRoT-9 b is 1,347.0 light-years (413.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,347 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 23,707,200 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-9 b scores 0.29, ranking #2,063 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: CoRoT-9
CoRoT-9 b belongs to a system of 2 stars; it orbits CoRoT-9.
CoRoT-9
- Surface temperature
- 5,625 K (Sun: 5,772 K)
- Mass
- 0.96 M☉
- Radius
- 0.96 R☉
- Age
- 6.0 billion years (Sun: 4.6)
Planetary System
CoRoT-9 b is the only planet known to orbit CoRoT-9 so far.
CoRoT-9 b — Complete Data
| Radius | 11.949 Earth radii (1.066 Jupiter radii) |
|---|---|
| Mass | 266.98 Earth masses (0.840 Jupiter masses) |
| Density | 0.86 g/cm³ (Earth: 5.51) |
| Orbital period | 95.27 days |
| Orbital distance | 0.402 AU |
| Eccentricity | 0.133 |
| Equilibrium temperature | 420 K (147 °C) |
| Earth Similarity Index | 0.29 |
| Distance from Earth | 1,347.0 light-years (413.0 parsecs) |
| Constellation | Serpens |
| Discovery method | Transit |
| Discovery facility | CoRoT |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2017-12-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About CoRoT-9 b
Is CoRoT-9 b habitable?
No — CoRoT-9 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is CoRoT-9 b?
CoRoT-9 b is about 1,347 light-years from Earth in the constellation Serpens. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 23,707,200 years to get there.
How big is CoRoT-9 b compared to Earth?
CoRoT-9 b has 11.95 times the radius of Earth and about 267 times its mass.
How long is a year on CoRoT-9 b?
One orbit around CoRoT-9 takes 95.3 Earth days.
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