EPIC 246851721 b

Astrophysical Synthesis & Habitability Characterization

EPIC 246851721 b is a confirmed gas giant exoplanet orbiting the star EPIC 246851721, located approximately 1215.4 light-years (372.63 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.4638% across the stellar disk), this world measures 11.781 Earth radii (1.05 Jupiter radii) and has a measured mass of 953.49 Earth masses (3 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.22 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.87 g⊕ (67.37 m/s²), and an escape velocity of 100.6 km/s.

In its orbital architecture around EPIC 246851721, EPIC 246851721 b completes one full revolution every 6.18 Earth days at a semi-major axis of 0.07229 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 127.3 km/s (compared to Earth's 29.8 km/s).

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 1401 K (+1128°C / +2062°F) and receiving 642.00 S⊕ (~873,762 W/m²), EPIC 246851721 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star EPIC 246851721 is classified as a warm F-type star of spectral type F5 V with an effective photospheric temperature of 6,202 K, a radius of 1.586 R☉, a mass of 1.317 M☉, an estimated bolometric luminosity of 3.339 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.02 Gyr and a metallicity of [Fe/H] = 0.141 dex (metal-rich relative to the Sun). From Earth, EPIC 246851721 shines at apparent V-band magnitude 11.237 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).