HD 25912 b
Astrophysical Synthesis & Habitability Characterization
HD 25912 b is a confirmed gas giant exoplanet orbiting the star HD 25912, located approximately 160.4 light-years (49.17 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 6.9 Earth radii (0.62 Jupiter radii) and has a measured mass of 38.139 Earth masses (0.12 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.64 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.8 g⊕ (7.85 m/s²), and an escape velocity of 26.3 km/s.
In its orbital architecture around HD 25912, HD 25912 b completes one full revolution every 41.832 Earth days at a semi-major axis of 0.242 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 62.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.05 carries the world between 0.2299 AU at periapsis and 0.2541 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 579 K (+306°C / +583°F) and receiving 18.75 S⊕ (~25,516 W/m²), HD 25912 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 25912 is classified as a stellar host with an effective photospheric temperature of 5,921 K, a radius of 0.9959 R☉, a mass of 1.08 M☉, an estimated bolometric luminosity of 1.094 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, HD 25912 shines at apparent V-band magnitude 8.2 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 25912 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 25912 b sharing its stellar neighborhood alongside HD 25912 c.
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 25912 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,921 K |
| Stellar Radius | 0.9959 R☉ |
| Stellar Mass | 1.0800 M☉ |
| Bolometric Luminosity | 1.094 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.200 · G: 8.028 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.242000 AU |
| Orbital Period | 41.832 days |
| Mean Orbital Velocity | 62.9 km/s |
| Orbital Eccentricity (e) | 0.05000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.64 g/cm³ (26.3 km/s vesc) |
| Insolation Flux | 18.7477 S⊕ (~25,516 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 160.400 LY (49.166 pc) |