rho CrB c
Astrophysical Synthesis & Habitability Characterization
rho CrB c is a confirmed sub-neptune exoplanet orbiting the star rho CrB, located approximately 57 light-years (17.47 parsecs) from the Solar System. First announced in 2016 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 5.68 Earth radii (0.51 Jupiter radii) and has a measured mass of 27.442 Earth masses. Combining its mass and radius yields a mean bulk density of 0.83 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.85 g⊕ (8.34 m/s²), and an escape velocity of 24.6 km/s.
In its orbital architecture around rho CrB, rho CrB c completes one full revolution every 102.036 Earth days at a semi-major axis of 0.4206 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 44.8 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.048 (ranging from 0.4004 AU at periapsis to 0.4408 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 448 K (+175°C / +347°F) and receiving 9.85 S⊕ (~13,406 W/m²), rho CrB c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star rho CrB is classified as a solar-type yellow star of spectral type G0 with an effective photospheric temperature of 5,817 K, a radius of 1.3617 R☉, a mass of 1 M☉, an estimated bolometric luminosity of 1.905 L☉. Stellar evolution modeling indicates an estimated stellar age of 10.2 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, rho CrB shines at apparent V-band magnitude 5.408 (visible to the unaided human eye under dark skies) in the Northern celestial hemisphere. The rho CrB system is a multi-planet architecture hosting 3 confirmed worlds, with rho CrB c sharing its stellar neighborhood alongside rho CrB e, rho CrB b.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | rho CrB |
| Spectral Type | G0 |
| Effective Temp (Teff) | 5,817 K |
| Stellar Radius | 1.3617 R☉ |
| Stellar Mass | 1.0000 M☉ |
| Bolometric Luminosity | 1.905 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | 10.200 Gyr |
| Apparent Magnitude | V: 5.408 · G: 5.242 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.420600 AU |
| Orbital Period | 102.036 days |
| Mean Orbital Velocity | 44.8 km/s |
| Orbital Eccentricity (e) | 0.04800 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.83 g/cm³ (24.6 km/s vesc) |
| Insolation Flux | 9.8500 S⊕ (~13,406 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 57.000 LY (17.467 pc) |