Kepler-1669 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1669 c is a confirmed super-earth exoplanet orbiting the star Kepler-1669, located approximately 1772.5 light-years (543.44 parsecs) from the Solar System. First announced in 2021 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0835% across the stellar disk), this world measures 1.901 Earth radii and has a measured mass of 4.27 Earth masses. Combining its mass and radius yields a mean bulk density of 3.43 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.18 g⊕ (11.57 m/s²), and an escape velocity of 16.8 km/s.
In its orbital architecture around Kepler-1669, Kepler-1669 c completes one full revolution every 1.609 Earth days at a semi-major axis of 0.0228 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 154.1 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 958 K (+685°C / +1265°F) and receiving 199.28 S⊕ (~271,220 W/m²), Kepler-1669 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1669 is classified as a stellar host with an effective photospheric temperature of 4,224 K, a radius of 0.603 R☉, a mass of 0.609 M☉, an estimated bolometric luminosity of 0.104 L☉. Stellar evolution modeling indicates an estimated stellar age of 13.9 Gyr and a metallicity of [Fe/H] = -0.2 dex (metal-poor relative to the Sun). From Earth, Kepler-1669 shines at apparent V-band magnitude 16.473 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1669 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-1669 c sharing its stellar neighborhood alongside Kepler-1669 d, Kepler-1669 b.
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-1669 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,224 K |
| Stellar Radius | 0.6030 R☉ |
| Stellar Mass | 0.6090 M☉ |
| Bolometric Luminosity | 0.104 L☉ |
| Metallicity [Fe/H] | -0.200 dex |
| Stellar Age | 13.900 Gyr |
| Apparent Magnitude | V: 16.473 · G: 15.909 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.022800 AU |
| Orbital Period | 1.609 days |
| Mean Orbital Velocity | 154.1 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.8900° |
| Mean Bulk Density | 3.43 g/cm³ (16.8 km/s vesc) |
| Insolation Flux | 199.2800 S⊕ (~271,220 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1772.500 LY (543.444 pc) |