HD 63935 c
Astrophysical Synthesis & Habitability Characterization
HD 63935 c is a confirmed sub-neptune exoplanet orbiting the star HD 63935, located approximately 159.7 light-years (48.97 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 3.065 Earth radii (0.27 Jupiter radii) and has a measured mass of 11.1 Earth masses. Combining its mass and radius yields a mean bulk density of 2.13 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.18 g⊕ (11.57 m/s²), and an escape velocity of 21.3 km/s.
In its orbital architecture around HD 63935, HD 63935 c completes one full revolution every 21.403 Earth days at a semi-major axis of 0.148 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 75.2 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 620 K (+347°C / +657°F) and receiving 36.70 S⊕ (~49,949 W/m²), HD 63935 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 63935 is classified as a stellar host with an effective photospheric temperature of 5,513 K, a radius of 0.9598 R☉, a mass of 0.9406 M☉, an estimated bolometric luminosity of 0.763 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.6 Gyr and a metallicity of [Fe/H] = 0.107 dex (metal-rich relative to the Sun). From Earth, HD 63935 shines at apparent V-band magnitude 8.58 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 63935 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 63935 c sharing its stellar neighborhood alongside HD 63935 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 | HD 63935 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,513 K |
| Stellar Radius | 0.9598 R☉ |
| Stellar Mass | 0.9406 M☉ |
| Bolometric Luminosity | 0.763 L☉ |
| Metallicity [Fe/H] | 0.107 dex |
| Stellar Age | 6.600 Gyr |
| Apparent Magnitude | V: 8.580 · G: 8.394 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.148000 AU |
| Orbital Period | 21.403 days |
| Mean Orbital Velocity | 75.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.2410° |
| Mean Bulk Density | 2.13 g/cm³ (21.3 km/s vesc) |
| Insolation Flux | 36.7000 S⊕ (~49,949 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 159.700 LY (48.974 pc) |