Kepler-1504 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1504 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1504, located approximately 7945 light-years (2435.94 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0581% across the stellar disk), this world measures 2.13 Earth radii and has a measured mass of 5.18 Earth masses. Combining its mass and radius yields a mean bulk density of 2.96 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.14 g⊕ (11.18 m/s²), and an escape velocity of 17.4 km/s.

In its orbital architecture around Kepler-1504, Kepler-1504 b completes one full revolution every 82.304 Earth days at a semi-major axis of 0.3704 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 49 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 485 K (+212°C / +414°F) and receiving 25.17 S⊕ (~34,256 W/m²), Kepler-1504 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1504 is classified as a stellar host with an effective photospheric temperature of 5,393 K, a radius of 0.81 R☉, a mass of 0.85 M☉, an estimated bolometric luminosity of 0.498 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, Kepler-1504 shines at apparent V-band magnitude 15.883 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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