Kepler-1601 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1601 b is a confirmed terrestrial exoplanet orbiting the star Kepler-1601, located approximately 2101.9 light-years (644.46 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0049% across the stellar disk), this world measures 0.82 Earth radii and has a measured mass of 0.477 Earth masses. Combining its mass and radius yields a mean bulk density of 4.77 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.71 g⊕ (6.96 m/s²), and an escape velocity of 8.5 km/s.
In its orbital architecture around Kepler-1601, Kepler-1601 b completes one full revolution every 2.209 Earth days at a semi-major axis of 0.03281 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 161.6 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 1507 K (+1234°C / +2253°F) and receiving 999.75 S⊕ (~1,360,662 W/m²), Kepler-1601 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1601 is classified as a stellar host with an effective photospheric temperature of 5,869 K, a radius of 1.07 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 1.219 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.27 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, Kepler-1601 shines at apparent V-band magnitude 13.842 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Kepler · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | Kepler-1601 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,869 K |
| Stellar Radius | 1.0700 R☉ |
| Stellar Mass | 1.0400 M☉ |
| Bolometric Luminosity | 1.219 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 4.270 Gyr |
| Apparent Magnitude | V: 13.842 · G: 13.678 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.032810 AU |
| Orbital Period | 2.209 days |
| Mean Orbital Velocity | 161.6 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.1100° |
| Mean Bulk Density | 4.77 g/cm³ (8.5 km/s vesc) |
| Insolation Flux | 999.7520 S⊕ (~1,360,662 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2101.900 LY (644.456 pc) |