Kepler-1725 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1725 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-1725, located approximately 1822.1 light-years (558.65 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0565% across the stellar disk), this world measures 2.813 Earth radii and has a measured mass of 8.31 Earth masses. Combining its mass and radius yields a mean bulk density of 2.06 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.05 g⊕ (10.3 m/s²), and an escape velocity of 19.2 km/s.

In its orbital architecture around Kepler-1725, Kepler-1725 b completes one full revolution every 16.72 Earth days at a semi-major axis of 0.13263 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 86.3 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 767 K (+494°C / +921°F) and receiving 84.10 S⊕ (~114,460 W/m²), Kepler-1725 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1725 is classified as a stellar host with an effective photospheric temperature of 6,020 K, a radius of 1.085 R☉, a mass of 1.049 M☉, an estimated bolometric luminosity of 1.387 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.89 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-1725 shines at apparent V-band magnitude 13.153 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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