HD 24085 b
Astrophysical Synthesis & Habitability Characterization
HD 24085 b is a confirmed sub-neptune exoplanet orbiting the star HD 24085, located approximately 179.1 light-years (54.9 parsecs) from the Solar System. First announced in 2019 by Las Campanas Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 3.46 Earth radii (0.31 Jupiter radii) and has a measured mass of 11.8 Earth masses. Combining its mass and radius yields a mean bulk density of 1.57 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.99 g⊕ (9.71 m/s²), and an escape velocity of 20.7 km/s.
In its orbital architecture around HD 24085, HD 24085 b completes one full revolution every 2.046 Earth days at a semi-major axis of 0.034 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 180.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.22 carries the world between 0.0265 AU at periapsis and 0.0415 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1875 K (+1602°C / +2916°F) and receiving 2,061.42 S⊕ (~2,805,591 W/m²), HD 24085 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 24085 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 6,034 K, a radius of 1.4126 R☉, a mass of 1.22 M☉, an estimated bolometric luminosity of 2.373 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.17 dex (metal-rich relative to the Sun). From Earth, HD 24085 shines at apparent V-band magnitude 7.57 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.
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: Las Campanas Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 24085 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 6,034 K |
| Stellar Radius | 1.4126 R☉ |
| Stellar Mass | 1.2200 M☉ |
| Bolometric Luminosity | 2.373 L☉ |
| Metallicity [Fe/H] | 0.170 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.570 · G: 7.425 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.034000 AU |
| Orbital Period | 2.046 days |
| Mean Orbital Velocity | 180.8 km/s |
| Orbital Eccentricity (e) | 0.22000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.57 g/cm³ (20.7 km/s vesc) |
| Insolation Flux | 2061.4187 S⊕ (~2,805,591 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 179.100 LY (54.900 pc) |