HD 136925 b
Astrophysical Synthesis & Habitability Characterization
HD 136925 b is a confirmed gas giant exoplanet orbiting the star HD 136925, located approximately 156.1 light-years (47.87 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 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 266.976 Earth masses (0.84 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.55 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.38 g⊕ (13.53 m/s²), and an escape velocity of 49 km/s.
In its orbital architecture around HD 136925, HD 136925 b completes one full revolution every 4540 Earth days (12.43Julian years) at a semi-major axis of 5.13 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 12.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.103 carries the world between 4.6016 AU at periapsis and 5.6584 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 134 K (-139°C / -218°F) and an incident flux of 0.05 S⊕ (~70 W/m²), surface water and volatile species on HD 136925 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 136925 is classified as a stellar host with an effective photospheric temperature of 5,773 K, a radius of 1.1931 R☉, a mass of 0.8751 M☉, an estimated bolometric luminosity of 1.419 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.217 dex (metal-poor relative to the Sun). From Earth, HD 136925 shines at apparent V-band magnitude 7.914 (accessible to binoculars and small amateur telescopes) in the Northern 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 136925 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,773 K |
| Stellar Radius | 1.1931 R☉ |
| Stellar Mass | 0.8751 M☉ |
| Bolometric Luminosity | 1.419 L☉ |
| Metallicity [Fe/H] | -0.217 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.914 · G: 7.744 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.130000 AU |
| Orbital Period | 4540 days |
| Mean Orbital Velocity | 12.3 km/s |
| Orbital Eccentricity (e) | 0.10300 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.55 g/cm³ (49 km/s vesc) |
| Insolation Flux | 0.0518 S⊕ (~70 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 156.100 LY (47.874 pc) |