K2-237 b
Astrophysical Synthesis & Habitability Characterization
K2-237 b is a confirmed gas giant exoplanet orbiting the star K2-237, located approximately 1027.4 light-years (315 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 1.4194% across the stellar disk), this world measures 16.062 Earth radii (1.43 Jupiter radii) and has a measured mass of 434.154 Earth masses (1.37 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.58 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.68 g⊕ (16.48 m/s²), and an escape velocity of 58.2 km/s.
In its orbital architecture around K2-237, K2-237 b completes one full revolution every 2.181 Earth days at a semi-major axis of 0.03552 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 177.2 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.03 (ranging from 0.0345 AU at periapsis to 0.0366 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1759 K (+1486°C / +2707°F) and receiving 1,860.00 S⊕ (~2,531,460 W/m²), K2-237 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-237 is classified as a warm F-type star of spectral type F9 V with an effective photospheric temperature of 6,180 K, a radius of 1.236 R☉, a mass of 1.256 M☉, an estimated bolometric luminosity of 1.999 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.09 Gyr and a metallicity of [Fe/H] = 0.337 dex (metal-rich relative to the Sun). From Earth, K2-237 shines at apparent V-band magnitude 11.602 (faint and requiring research-grade or CCD telescopic photometry) 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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | K2-237 |
| Spectral Type | F9 V |
| Effective Temp (Teff) | 6,180 K |
| Stellar Radius | 1.2360 R☉ |
| Stellar Mass | 1.2560 M☉ |
| Bolometric Luminosity | 1.999 L☉ |
| Metallicity [Fe/H] | 0.337 dex |
| Stellar Age | 1.090 Gyr |
| Apparent Magnitude | V: 11.602 · G: 11.467 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.035520 AU |
| Orbital Period | 2.181 days |
| Mean Orbital Velocity | 177.2 km/s |
| Orbital Eccentricity (e) | 0.03000 |
| Orbital Inclination (i) | 88.3700° |
| Mean Bulk Density | 0.58 g/cm³ (58.2 km/s vesc) |
| Insolation Flux | 1860.0000 S⊕ (~2,531,460 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1027.400 LY (314.995 pc) |