HD 135625 b
Astrophysical Synthesis & Habitability Characterization
HD 135625 b is a confirmed gas giant exoplanet orbiting the star HD 135625, located approximately 184.3 light-years (56.52 parsecs) from the Solar System. First announced in 2023 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.3 Earth radii (1.19 Jupiter radii) and has a measured mass of 731.005 Earth masses (2.3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.71 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.13 g⊕ (40.5 m/s²), and an escape velocity of 82.9 km/s.
In its orbital architecture around HD 135625, HD 135625 b completes one full revolution every 4055 Earth days (11.1Julian years) at a semi-major axis of 5.4 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 14.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.16 carries the world between 4.536 AU at periapsis and 6.264 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 146 K (-127°C / -197°F) and an incident flux of 0.08 S⊕ (~103 W/m²), surface water and volatile species on HD 135625 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 135625 is classified as a solar-type yellow star of spectral type G3 IV/V with an effective photospheric temperature of 6,041 K, a radius of 1.3574 R☉, a mass of 1.28 M☉, an estimated bolometric luminosity of 2.202 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.4 Gyr and a metallicity of [Fe/H] = 0.12 dex (metal-rich relative to the Sun). From Earth, HD 135625 shines at apparent V-band magnitude 7.72 (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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 135625 |
| Spectral Type | G3 IV/V |
| Effective Temp (Teff) | 6,041 K |
| Stellar Radius | 1.3574 R☉ |
| Stellar Mass | 1.2800 M☉ |
| Bolometric Luminosity | 2.202 L☉ |
| Metallicity [Fe/H] | 0.120 dex |
| Stellar Age | 4.400 Gyr |
| Apparent Magnitude | V: 7.720 · G: 7.566 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 5.400000 AU |
| Orbital Period | 4055 days |
| Mean Orbital Velocity | 14.5 km/s |
| Orbital Eccentricity (e) | 0.16000 |
| Orbital Inclination (i) | 93.0000° |
| Mean Bulk Density | 1.71 g/cm³ (82.9 km/s vesc) |
| Insolation Flux | 0.0758 S⊕ (~103 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 184.300 LY (56.518 pc) |