Kepler-726 b

Astrophysical Synthesis & Habitability Characterization

Kepler-726 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-726, located approximately 2485.6 light-years (762.08 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.1236% across the stellar disk), this world measures 3.26 Earth radii (0.29 Jupiter radii) and has a measured mass of 10.7 Earth masses. Combining its mass and radius yields a mean bulk density of 1.7 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.01 g⊕ (9.9 m/s²), and an escape velocity of 20.3 km/s.

In its orbital architecture around Kepler-726, Kepler-726 b completes one full revolution every 21.805 Earth days at a semi-major axis of 0.1406 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 70.2 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 543 K (+270°C / +518°F) and receiving 25.30 S⊕ (~34,428 W/m²), Kepler-726 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-726 is classified as a stellar host with an effective photospheric temperature of 5,452 K, a radius of 0.85 R☉, a mass of 0.88 M☉, an estimated bolometric luminosity of 0.573 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.47 Gyr and a metallicity of [Fe/H] = -0.09 dex (near-solar heavy-element abundance). From Earth, Kepler-726 shines at apparent V-band magnitude 15.362 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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