HD 179949 b
Astrophysical Synthesis & Habitability Characterization
HD 179949 b is a confirmed gas giant exoplanet orbiting the star HD 179949, located approximately 89.6 light-years (27.46 parsecs) from the Solar System. First announced in 2000 by Anglo-Australian Telescope 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 291.12 Earth masses (0.92 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.6 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.51 g⊕ (14.81 m/s²), and an escape velocity of 51.2 km/s.
In its orbital architecture around HD 179949, HD 179949 b completes one full revolution every 3.093 Earth days at a semi-major axis of 0.0443 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 155.8 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.022 (ranging from 0.0433 AU at periapsis to 0.0453 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1591 K (+1318°C / +2404°F) and receiving 1,020.12 S⊕ (~1,388,382 W/m²), HD 179949 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 179949 is classified as a warm F-type star of spectral type F8 V with an effective photospheric temperature of 6,168 K, a radius of 1.2669 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 2.084 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.56 Gyr and a metallicity of [Fe/H] = 0.137 dex (metal-rich relative to the Sun). From Earth, HD 179949 shines at apparent V-band magnitude 6.25 (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: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 179949 |
| Spectral Type | F8 V |
| Effective Temp (Teff) | 6,168 K |
| Stellar Radius | 1.2669 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 2.084 L☉ |
| Metallicity [Fe/H] | 0.137 dex |
| Stellar Age | 2.560 Gyr |
| Apparent Magnitude | V: 6.250 · G: 6.111 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.044300 AU |
| Orbital Period | 3.093 days |
| Mean Orbital Velocity | 155.8 km/s |
| Orbital Eccentricity (e) | 0.02200 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.6 g/cm³ (51.2 km/s vesc) |
| Insolation Flux | 1020.1193 S⊕ (~1,388,382 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 89.600 LY (27.457 pc) |