HAT-P-37 b
Astrophysical Synthesis & Habitability Characterization
HAT-P-37 b is a confirmed gas giant exoplanet orbiting the star HAT-P-37, located approximately 1273.9 light-years (390.59 parsecs) from the Solar System. First announced in 2011 by HATNet using the Transit detection technique (producing an estimated primary transit depth of 1.9053% across the stellar disk), this world measures 13.204 Earth radii (1.18 Jupiter radii) and has a measured mass of 371.528 Earth masses (1.17 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.89 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.13 g⊕ (20.89 m/s²), and an escape velocity of 59.3 km/s.
In its orbital architecture around HAT-P-37, HAT-P-37 b completes one full revolution every 2.797 Earth days at a semi-major axis of 0.0379 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 147.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.058 carries the world between 0.0357 AU at periapsis and 0.0401 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1271 K (+998°C / +1828°F) and receiving 412.39 S⊕ (~561,265 W/m²), HAT-P-37 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HAT-P-37 is classified as a stellar host with an effective photospheric temperature of 5,500 K, a radius of 0.877 R☉, a mass of 0.929 M☉, an estimated bolometric luminosity of 0.631 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.6 Gyr and a metallicity of [Fe/H] = 0.03 dex (near-solar heavy-element abundance). From Earth, HAT-P-37 shines at apparent V-band magnitude 13.427 (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-37 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,500 K |
| Stellar Radius | 0.8770 R☉ |
| Stellar Mass | 0.9290 M☉ |
| Bolometric Luminosity | 0.631 L☉ |
| Metallicity [Fe/H] | 0.030 dex |
| Stellar Age | 3.600 Gyr |
| Apparent Magnitude | V: 13.427 · G: 13.262 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.037900 AU |
| Orbital Period | 2.797 days |
| Mean Orbital Velocity | 147.4 km/s |
| Orbital Eccentricity (e) | 0.05800 |
| Orbital Inclination (i) | 86.9000° |
| Mean Bulk Density | 0.89 g/cm³ (59.3 km/s vesc) |
| Insolation Flux | 412.3914 S⊕ (~561,265 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1273.900 LY (390.594 pc) |