Kepler-1732 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1732 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1732, located approximately 4205.5 light-years (1289.41 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0633% across the stellar disk), this world measures 4.099 Earth radii (0.37 Jupiter radii) and has a measured mass of 15.7 Earth masses. Combining its mass and radius yields a mean bulk density of 1.26 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.93 g⊕ (9.12 m/s²), and an escape velocity of 21.9 km/s.

In its orbital architecture around Kepler-1732, Kepler-1732 b completes one full revolution every 32.312 Earth days at a semi-major axis of 0.2015 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 67.8 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 699 K (+426°C / +799°F) and receiving 27.05 S⊕ (~36,815 W/m²), Kepler-1732 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1732 is classified as a stellar host with an effective photospheric temperature of 5,821 K, a radius of 1.494 R☉, a mass of 1.043 M☉, an estimated bolometric luminosity of 2.299 L☉. Stellar evolution modeling indicates an estimated stellar age of 2 Gyr and a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1732 shines at apparent V-band magnitude 14.884 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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