HD 1502 b
Astrophysical Synthesis & Habitability Characterization
HD 1502 b is a confirmed gas giant exoplanet orbiting the star HD 1502, located approximately 622.8 light-years (190.95 parsecs) from the Solar System. First announced in 2011 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 874.033 Earth masses (2.75 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.1 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 5.02 g⊕ (49.23 m/s²), and an escape velocity of 91 km/s.
In its orbital architecture around HD 1502, HD 1502 b completes one full revolution every 428.5 Earth days (1.17Julian years) at a semi-major axis of 1.262 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 32 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.031 (ranging from 1.2229 AU at periapsis to 1.3011 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 459 K (+186°C / +367°F) and receiving 7.28 S⊕ (~9,913 W/m²), HD 1502 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 1502 is classified as an orange K-type star of spectral type K0 with an effective photospheric temperature of 4,947 K, a radius of 4.67 R☉, a mass of 1.46 M☉, an estimated bolometric luminosity of 11.719 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.4 Gyr and a metallicity of [Fe/H] = 0.09 dex (metal-rich relative to the Sun). From Earth, HD 1502 shines at apparent V-band magnitude 8.36 (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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 1502 |
| Spectral Type | K0 |
| Effective Temp (Teff) | 4,947 K |
| Stellar Radius | 4.6700 R☉ |
| Stellar Mass | 1.4600 M☉ |
| Bolometric Luminosity | 11.719 L☉ |
| Metallicity [Fe/H] | 0.090 dex |
| Stellar Age | 2.400 Gyr |
| Apparent Magnitude | V: 8.360 · G: 8.104 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.262000 AU |
| Orbital Period | 428.5 days |
| Mean Orbital Velocity | 32 km/s |
| Orbital Eccentricity (e) | 0.03100 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.1 g/cm³ (91 km/s vesc) |
| Insolation Flux | 7.2835 S⊕ (~9,913 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 622.800 LY (190.953 pc) |