HD 23079 c
Astrophysical Synthesis & Habitability Characterization
HD 23079 c is a confirmed sub-neptune exoplanet orbiting the star HD 23079, located approximately 109.1 light-years (33.46 parsecs) from the Solar System. First announced in 2025 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.8 Earth radii and has a measured mass of 8.26 Earth masses. Combining its mass and radius yields a mean bulk density of 2.07 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 19.2 km/s.
In its orbital architecture around HD 23079, HD 23079 c completes one full revolution every 5.749 Earth days. Its moderate orbital eccentricity of e = 0.097 driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 2.800 R⊕, HD 23079 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 HD 23079 is classified as a warm F-type star of spectral type F9.5 V with an effective photospheric temperature of 5,994 K, a radius of 1.08 R☉, a mass of 1.16 M☉, an estimated bolometric luminosity of 1.351 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.6 Gyr and a metallicity of [Fe/H] = -0.129 dex (metal-poor relative to the Sun). From Earth, HD 23079 shines at apparent V-band magnitude 7.12 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 23079 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 23079 c sharing its stellar neighborhood alongside HD 23079 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 23079 |
| Spectral Type | F9.5 V |
| Effective Temp (Teff) | 5,994 K |
| Stellar Radius | 1.0800 R☉ |
| Stellar Mass | 1.1600 M☉ |
| Bolometric Luminosity | 1.351 L☉ |
| Metallicity [Fe/H] | -0.129 dex |
| Stellar Age | 2.600 Gyr |
| Apparent Magnitude | V: 7.120 · G: 6.962 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 5.749 days |
| Orbital Eccentricity (e) | 0.09700 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.07 g/cm³ (19.2 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 109.100 LY (33.459 pc) |