HD 93963 A c
Astrophysical Synthesis & Habitability Characterization
HD 93963 A c is a confirmed sub-neptune exoplanet orbiting the star HD 93963 A, located approximately 268.6 light-years (82.34 parsecs) from the Solar System. First announced in 2022 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.077% across the stellar disk), this world measures 3.12 Earth radii (0.28 Jupiter radii) and has a measured mass of 18.4 Earth masses. Combining its mass and radius yields a mean bulk density of 3.34 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.89 g⊕ (18.53 m/s²), and an escape velocity of 27.2 km/s.
In its orbital architecture around HD 93963 A, HD 93963 A c completes one full revolution every 3.645 Earth days at a semi-major axis of 0.04726 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 141 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 1212 K (+939°C / +1722°F) and receiving 543.80 S⊕ (~740,112 W/m²), HD 93963 A c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 93963 A is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,908 K, a radius of 1.0311 R☉, a mass of 1.0844 M☉, an estimated bolometric luminosity of 1.162 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.3 Gyr and a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, HD 93963 A shines at apparent V-band magnitude 9.182 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 93963 A system is a multi-planet architecture hosting 2 confirmed worlds, with HD 93963 A c sharing its stellar neighborhood alongside HD 93963 A 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 93963 A |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,908 K |
| Stellar Radius | 1.0311 R☉ |
| Stellar Mass | 1.0844 M☉ |
| Bolometric Luminosity | 1.162 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | 1.300 Gyr |
| Apparent Magnitude | V: 9.182 · G: 9.034 |
| System Architecture | 2 Stars, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.047260 AU |
| Orbital Period | 3.645 days |
| Mean Orbital Velocity | 141 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.3100° |
| Mean Bulk Density | 3.34 g/cm³ (27.2 km/s vesc) |
| Insolation Flux | 543.8000 S⊕ (~740,112 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 268.600 LY (82.343 pc) |