Kepler-655 b

Astrophysical Synthesis & Habitability Characterization

Kepler-655 b is a confirmed sub-neptune exoplanet orbiting the star Kepler-655, located approximately 2454.5 light-years (752.56 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0401% across the stellar disk), this world measures 2.71 Earth radii and has a measured mass of 7.8 Earth masses. Combining its mass and radius yields a mean bulk density of 2.16 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.06 g⊕ (10.4 m/s²), and an escape velocity of 19 km/s.

In its orbital architecture around Kepler-655, Kepler-655 b completes one full revolution every 46.406 Earth days at a semi-major axis of 0.25697 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 60.2 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 588 K (+315°C / +599°F) and receiving 28.77 S⊕ (~39,152 W/m²), Kepler-655 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star Kepler-655 is classified as a stellar host with an effective photospheric temperature of 6,170 K, a radius of 1.24 R☉, a mass of 1.15 M☉, an estimated bolometric luminosity of 1.999 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.39 Gyr and a metallicity of [Fe/H] = 0 dex (near-solar heavy-element abundance). From Earth, Kepler-655 shines at apparent V-band magnitude 13.568 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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