Kepler-1137 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1137 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1137, located approximately 3006.4 light-years (921.78 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.012% across the stellar disk), this world measures 2.2 Earth radii and has a measured mass of 5.48 Earth masses. Combining its mass and radius yields a mean bulk density of 2.84 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.13 g⊕ (11.08 m/s²), and an escape velocity of 17.7 km/s.

In its orbital architecture around Kepler-1137, Kepler-1137 b completes one full revolution every 23.921 Earth days at a semi-major axis of 0.1871 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 85.1 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 1020 K (+747°C / +1377°F) and receiving 197.85 S⊕ (~269,268 W/m²), Kepler-1137 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1137 is classified as a stellar host with an effective photospheric temperature of 6,807 K, a radius of 1.84 R☉, a mass of 1.5 M☉, an estimated bolometric luminosity of 6.522 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.58 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-1137 shines at apparent V-band magnitude 12.827 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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