HD 208527 b
Astrophysical Synthesis & Habitability Characterization
HD 208527 b is a confirmed gas giant exoplanet orbiting the star HD 208527, located approximately 1018.3 light-years (312.2 parsecs) from the Solar System. First announced in 2012 by Bohyunsan Optical Astronomical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 3146.4 Earth masses (9.9 Jupiter masses). Combining its mass and radius yields a mean bulk density of 8.88 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 20.14 g⊕ (197.51 m/s²), and an escape velocity of 177.5 km/s.
In its orbital architecture around HD 208527, HD 208527 b completes one full revolution every 875.5 Earth days (2.4Julian years) at a semi-major axis of 2.1 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 26.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.08 carries the world between 1.932 AU at periapsis and 2.268 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 960 K (+687°C / +1269°F) and receiving 165.49 S⊕ (~225,237 W/m²), HD 208527 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 208527 is classified as a low-mass red dwarf of spectral type M1 III with an effective photospheric temperature of 4,035 K, a radius of 51.1 R☉, a mass of 1.6 M☉, an estimated bolometric luminosity of 621.02 L☉. Stellar evolution modeling indicates an estimated stellar age of 2 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, HD 208527 shines at apparent V-band magnitude 6.39 (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: Bohyunsan Optical Astronomical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 208527 |
| Spectral Type | M1 III |
| Effective Temp (Teff) | 4,035 K |
| Stellar Radius | 51.1000 R☉ |
| Stellar Mass | 1.6000 M☉ |
| Bolometric Luminosity | 621.02 L☉ |
| Metallicity [Fe/H] | -0.090 dex |
| Stellar Age | 2.000 Gyr |
| Apparent Magnitude | V: 6.390 · G: 5.616 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.100000 AU |
| Orbital Period | 875.5 days |
| Mean Orbital Velocity | 26.1 km/s |
| Orbital Eccentricity (e) | 0.08000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 8.88 g/cm³ (177.5 km/s vesc) |
| Insolation Flux | 165.4934 S⊕ (~225,237 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1018.300 LY (312.202 pc) |