HD 285507 b
Astrophysical Synthesis & Habitability Characterization
HD 285507 b is a confirmed gas giant exoplanet orbiting the star HD 285507, located approximately 146.9 light-years (45.03 parsecs) from the Solar System. First announced in 2013 by Fred Lawrence Whipple Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.8 Earth radii (1.23 Jupiter radii) and has a measured mass of 311.473 Earth masses (0.98 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.65 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.64 g⊕ (16.08 m/s²), and an escape velocity of 53.1 km/s.
In its orbital architecture around HD 285507, HD 285507 b completes one full revolution every 6.088 Earth days at a semi-major axis of 0.06 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 107.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.09 carries the world between 0.0546 AU at periapsis and 0.0654 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 736 K (+463°C / +865°F) and receiving 53.01 S⊕ (~72,150 W/m²), HD 285507 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 285507 is classified as an orange K-type star of spectral type K4.5 V with an effective photospheric temperature of 4,503 K, a radius of 0.69 R☉, a mass of 0.82 M☉, an estimated bolometric luminosity of 0.176 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.625 Gyr and a metallicity of [Fe/H] = 0.13 dex (metal-rich relative to the Sun). From Earth, HD 285507 shines at apparent V-band magnitude 10.49 (faint and requiring research-grade or CCD telescopic photometry) 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: Fred Lawrence Whipple Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 285507 |
| Spectral Type | K4.5 V |
| Effective Temp (Teff) | 4,503 K |
| Stellar Radius | 0.6900 R☉ |
| Stellar Mass | 0.8200 M☉ |
| Bolometric Luminosity | 0.176 L☉ |
| Metallicity [Fe/H] | 0.130 dex |
| Stellar Age | 0.625 Gyr |
| Apparent Magnitude | V: 10.490 · G: 10.040 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.060000 AU |
| Orbital Period | 6.088 days |
| Mean Orbital Velocity | 107.2 km/s |
| Orbital Eccentricity (e) | 0.09000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.65 g/cm³ (53.1 km/s vesc) |
| Insolation Flux | 53.0123 S⊕ (~72,150 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 146.900 LY (45.029 pc) |