Kepler-1951 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1951 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1951, located approximately 4166.1 light-years (1277.32 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0265% across the stellar disk), this world measures 2.321 Earth radii and has a measured mass of 6 Earth masses. Combining its mass and radius yields a mean bulk density of 2.65 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 18 km/s.

In its orbital architecture around Kepler-1951, Kepler-1951 b completes one full revolution every 20.658 Earth days at a semi-major axis of 0.1435 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 75.6 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 728 K (+455°C / +851°F) and receiving 66.27 S⊕ (~90,193 W/m²), Kepler-1951 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1951 is classified as a stellar host with an effective photospheric temperature of 5,468 K, a radius of 1.306 R☉, a mass of 0.923 M☉, an estimated bolometric luminosity of 1.368 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, Kepler-1951 shines at apparent V-band magnitude 14.367 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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