Kepler-1823 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1823 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1823, located approximately 2364.5 light-years (724.97 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0288% across the stellar disk), this world measures 2.086 Earth radii and has a measured mass of 5 Earth masses. Combining its mass and radius yields a mean bulk density of 3.04 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.3 km/s.

In its orbital architecture around Kepler-1823, Kepler-1823 b completes one full revolution every 21.103 Earth days at a semi-major axis of 0.15332 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 79 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 718 K (+445°C / +833°F) and receiving 78.00 S⊕ (~106,158 W/m²), Kepler-1823 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1823 is classified as a stellar host with an effective photospheric temperature of 6,000 K, a radius of 1.126 R☉, a mass of 1.068 M☉, an estimated bolometric luminosity of 1.474 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.88 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, Kepler-1823 shines at apparent V-band magnitude 13.477 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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