Kepler-1990 c
Astrophysical Synthesis & Habitability Characterization
Kepler-1990 c is a confirmed terrestrial exoplanet orbiting the star Kepler-1990, located approximately 1280.9 light-years (392.74 parsecs) from the Solar System. First announced in 2023 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.007% across the stellar disk), this world measures 0.98 Earth radii and has a measured mass of 0.904 Earth masses. Combining its mass and radius yields a mean bulk density of 5.3 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 0.94 g⊕ (9.22 m/s²), and an escape velocity of 10.7 km/s.
In its orbital architecture around Kepler-1990, Kepler-1990 c completes one full revolution every 4.068 Earth days at a semi-major axis of 0.0504 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 134.8 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 1170 K (+897°C / +1647°F) and receiving 442.08 S⊕ (~601,671 W/m²), Kepler-1990 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1990 is classified as a stellar host with an effective photospheric temperature of 5,751 K, a radius of 1.071 R☉, a mass of 1.028 M☉, an estimated bolometric luminosity of 1.126 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.5 Gyr and a metallicity of [Fe/H] = 0.21 dex (metal-rich relative to the Sun). From Earth, Kepler-1990 shines at apparent V-band magnitude 11.946 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-1990 system is a multi-planet architecture hosting 2 confirmed worlds, with Kepler-1990 c sharing its stellar neighborhood alongside Kepler-1990 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-1990 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,751 K |
| Stellar Radius | 1.0710 R☉ |
| Stellar Mass | 1.0280 M☉ |
| Bolometric Luminosity | 1.126 L☉ |
| Metallicity [Fe/H] | 0.210 dex |
| Stellar Age | 2.500 Gyr |
| Apparent Magnitude | V: 11.946 · G: 12.583 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.050400 AU |
| Orbital Period | 4.068 days |
| Mean Orbital Velocity | 134.8 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.6100° |
| Mean Bulk Density | 5.3 g/cm³ (10.7 km/s vesc) |
| Insolation Flux | 442.0800 S⊕ (~601,671 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1280.900 LY (392.739 pc) |