Kepler-1617 b

Astrophysical Synthesis & Habitability Characterization

Kepler-1617 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1617, located approximately 2929.9 light-years (898.31 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0081% across the stellar disk), this world measures 1.2 Earth radii and has a measured mass of 1.87 Earth masses. Combining its mass and radius yields a mean bulk density of 5.97 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.3 g⊕ (12.75 m/s²), and an escape velocity of 14 km/s.

In its orbital architecture around Kepler-1617, Kepler-1617 b completes one full revolution every 27.479 Earth days at a semi-major axis of 0.17707 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 70.1 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 736 K (+463°C / +865°F) and receiving 64.69 S⊕ (~88,042 W/m²), Kepler-1617 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-1617 is classified as a stellar host with an effective photospheric temperature of 6,167 K, a radius of 1.22 R☉, a mass of 1.15 M☉, an estimated bolometric luminosity of 1.932 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.02 Gyr and a metallicity of [Fe/H] = 0.01 dex (near-solar heavy-element abundance). From Earth, Kepler-1617 shines at apparent V-band magnitude 13.811 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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