Kepler-1985 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1985 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1985. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0464% across the stellar disk), this world measures 2.27 Earth radii and has a measured mass of 5.77 Earth masses. Combining its mass and radius yields a mean bulk density of 2.72 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.12 g⊕ (10.98 m/s²), and an escape velocity of 17.8 km/s.

In its orbital architecture around Kepler-1985, Kepler-1985 b completes one full revolution every 3.421 Earth days at a semi-major axis of 0.0426 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 135.5 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 1129 K (+856°C / +1573°F) and receiving 382.68 S⊕ (~520,827 W/m²), Kepler-1985 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1985 is classified as a stellar host with an effective photospheric temperature of 5,370 K, a radius of 0.966 R☉, a mass of 0.877 M☉, an estimated bolometric luminosity of 0.696 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.14 dex (metal-rich relative to the Sun). From Earth, Kepler-1985 shines at apparent V-band magnitude 15.223 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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