IC 4651 9122 b
Astrophysical Synthesis & Habitability Characterization
IC 4651 9122 b is a confirmed gas giant exoplanet orbiting the star IC 4651 9122, located approximately 2802.7 light-years (859.32 parsecs) from the Solar System. First announced in 2018 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.7 Earth radii (1.13 Jupiter radii) and has a measured mass of 2002.329 Earth masses (6.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 5.39 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 12.41 g⊕ (121.7 m/s²), and an escape velocity of 140.5 km/s.
In its orbital architecture around IC 4651 9122, IC 4651 9122 b completes one full revolution every 734 Earth days (2.01Julian years) at a semi-major axis of 2.038 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 30.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.18 carries the world between 1.6712 AU at periapsis and 2.4048 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 513 K (+240°C / +464°F) and receiving 10.41 S⊕ (~14,169 W/m²), IC 4651 9122 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star IC 4651 9122 is classified as a stellar host with an effective photospheric temperature of 4,740 K, a radius of 10.2674 R☉, a mass of 2.1 M☉, an estimated bolometric luminosity of 47.745 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.14 Gyr and a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, IC 4651 9122 shines at apparent V-band magnitude 10.909 (faint and requiring research-grade or CCD telescopic photometry) in the Southern 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | IC 4651 9122 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,740 K |
| Stellar Radius | 10.2674 R☉ |
| Stellar Mass | 2.1000 M☉ |
| Bolometric Luminosity | 47.745 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | 1.140 Gyr |
| Apparent Magnitude | V: 10.909 · G: 10.534 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.038000 AU |
| Orbital Period | 734 days |
| Mean Orbital Velocity | 30.2 km/s |
| Orbital Eccentricity (e) | 0.18000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.39 g/cm³ (140.5 km/s vesc) |
| Insolation Flux | 10.4109 S⊕ (~14,169 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2802.700 LY (859.324 pc) |