HAT-P-16 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-16 b is a confirmed gas giant exoplanet orbiting the star HAT-P-16, located approximately 739.2 light-years (226.64 parsecs) from the Solar System. First announced in 2010 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.3515% across the stellar disk), this world measures 14.684 Earth radii (1.31 Jupiter radii) and has a measured mass of 1341.56 Earth masses (4.22 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.34 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.22 g⊕ (61 m/s²), and an escape velocity of 106.9 km/s.
In its orbital architecture around HAT-P-16, HAT-P-16 b completes one full revolution every 2.776 Earth days at a semi-major axis of 0.0413 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 161.9 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.0462 (ranging from 0.0394 AU at periapsis to 0.0432 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1566 K (+1293°C / +2359°F) and receiving 1,597.59 S⊕ (~2,174,320 W/m²), HAT-P-16 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-16 is classified as a warm F-type star of spectral type F8 with an effective photospheric temperature of 6,140 K, a radius of 1.158 R☉, a mass of 1.218 M☉, an estimated bolometric luminosity of 1.71 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.5 Gyr and a metallicity of [Fe/H] = 0.17 dex (metal-rich relative to the Sun). From Earth, HAT-P-16 shines at apparent V-band magnitude 10.911 (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: HATNet · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HAT-P-16 |
| Spectral Type | F8 |
| Effective Temp (Teff) | 6,140 K |
| Stellar Radius | 1.1580 R☉ |
| Stellar Mass | 1.2180 M☉ |
| Bolometric Luminosity | 1.71 L☉ |
| Metallicity [Fe/H] | 0.170 dex |
| Stellar Age | 0.500 Gyr |
| Apparent Magnitude | V: 10.911 · G: 10.757 |
| System Architecture | 3 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.041300 AU |
| Orbital Period | 2.776 days |
| Mean Orbital Velocity | 161.9 km/s |
| Orbital Eccentricity (e) | 0.04620 |
| Orbital Inclination (i) | 88.4000° |
| Mean Bulk Density | 2.34 g/cm³ (106.9 km/s vesc) |
| Insolation Flux | 1597.5900 S⊕ (~2,174,320 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 739.200 LY (226.637 pc) |