BD-11 4672 c
Astrophysical Synthesis & Habitability Characterization
BD-11 4672 c is a confirmed sub-neptune exoplanet orbiting the star BD-11 4672, located approximately 88.6 light-years (27.17 parsecs) from the Solar System. First announced in 2020 by Roque de los Muchachos Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 4.04 Earth radii (0.36 Jupiter radii) and has a measured mass of 15.37 Earth masses. Combining its mass and radius yields a mean bulk density of 1.29 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.94 g⊕ (9.22 m/s²), and an escape velocity of 21.8 km/s.
In its orbital architecture around BD-11 4672, BD-11 4672 c completes one full revolution every 74.2 Earth days at a semi-major axis of 0.3 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 44 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.4, swinging from 0.18 AU at periapsis out to 0.42 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 4.040 R⊕, BD-11 4672 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star BD-11 4672 is classified as an orange K-type star of spectral type K7V with an effective photospheric temperature of 4,550 K, a radius of 0.639 R☉, a mass of 0.651 M☉, an estimated bolometric luminosity of 0.157 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.4 Gyr and a metallicity of [Fe/H] = -0.35 dex (metal-poor relative to the Sun). From Earth, BD-11 4672 shines at apparent V-band magnitude 10.03 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The BD-11 4672 system is a multi-planet architecture hosting 2 confirmed worlds, with BD-11 4672 c sharing its stellar neighborhood alongside BD-11 4672 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: Roque de los Muchachos Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | BD-11 4672 |
| Spectral Type | K7V |
| Effective Temp (Teff) | 4,550 K |
| Stellar Radius | 0.6390 R☉ |
| Stellar Mass | 0.6510 M☉ |
| Bolometric Luminosity | 0.157 L☉ |
| Metallicity [Fe/H] | -0.350 dex |
| Stellar Age | 7.400 Gyr |
| Apparent Magnitude | V: 10.030 · G: 9.485 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.300000 AU |
| Orbital Period | 74.2 days |
| Mean Orbital Velocity | 44 km/s |
| Orbital Eccentricity (e) | 0.40000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.29 g/cm³ (21.8 km/s vesc) |
| Insolation Flux | 1.7444 S⊕ (~2,374 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 88.600 LY (27.167 pc) |