CoRoT-9 b
Astrophysical Synthesis & Habitability Characterization
CoRoT-9 b is a confirmed gas giant exoplanet orbiting the star CoRoT-9, located approximately 1347 light-years (412.98 parsecs) from the Solar System. First announced in 2009 by CoRoT using the Transit detection technique (producing an estimated primary transit depth of 1.3022% across the stellar disk), this world measures 11.949 Earth radii (1.07 Jupiter radii) and has a measured mass of 266.977 Earth masses (0.84 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.86 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.87 g⊕ (18.34 m/s²), and an escape velocity of 52.9 km/s.
In its orbital architecture around CoRoT-9, CoRoT-9 b completes one full revolution every 95.273 Earth days at a semi-major axis of 0.4021 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 45.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.133 carries the world between 0.3486 AU at periapsis and 0.4556 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 420 K (+147°C / +297°F) and receiving 3.44 S⊕ (~4,687 W/m²), CoRoT-9 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star CoRoT-9 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,625 K, a radius of 0.96 R☉, a mass of 0.96 M☉, an estimated bolometric luminosity of 0.828 L☉. Stellar evolution modeling indicates an estimated stellar age of 6 Gyr and a metallicity of [Fe/H] = -0.01 dex (near-solar heavy-element abundance). From Earth, CoRoT-9 shines at apparent V-band magnitude 13.637 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: CoRoT · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | CoRoT-9 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,625 K |
| Stellar Radius | 0.9600 R☉ |
| Stellar Mass | 0.9600 M☉ |
| Bolometric Luminosity | 0.828 L☉ |
| Metallicity [Fe/H] | -0.010 dex |
| Stellar Age | 6.000 Gyr |
| Apparent Magnitude | V: 13.637 · G: 13.501 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.402100 AU |
| Orbital Period | 95.273 days |
| Mean Orbital Velocity | 45.9 km/s |
| Orbital Eccentricity (e) | 0.13300 |
| Orbital Inclination (i) | 89.9000° |
| Mean Bulk Density | 0.86 g/cm³ (52.9 km/s vesc) |
| Insolation Flux | 3.4440 S⊕ (~4,687 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1347.000 LY (412.980 pc) |