Kepler-298 c
Astrophysical Synthesis & Habitability Characterization
Kepler-298 c is a confirmed super-earth exoplanet orbiting the star Kepler-298, located approximately 1690.2 light-years (518.2 parsecs) from the Solar System. First announced in 2014 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0924% across the stellar disk), this world measures 1.93 Earth radii and has a measured mass of 4.38 Earth masses. Combining its mass and radius yields a mean bulk density of 3.36 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 16.9 km/s.
In its orbital architecture around Kepler-298, Kepler-298 c completes one full revolution every 22.929 Earth days at a semi-major axis of 0.136 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 64.5 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 416 K (+143°C / +289°F) and receiving 8.70 S⊕ (~11,835 W/m²), Kepler-298 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-298 is classified as a stellar host with an effective photospheric temperature of 4,465 K, a radius of 0.582 R☉, a mass of 0.66 M☉, an estimated bolometric luminosity of 0.121 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.4 Gyr and a metallicity of [Fe/H] = -0.21 dex (metal-poor relative to the Sun). From Earth, Kepler-298 shines at apparent V-band magnitude 15.617 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-298 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-298 c sharing its stellar neighborhood alongside Kepler-298 b, Kepler-298 d.
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-298 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 4,465 K |
| Stellar Radius | 0.5820 R☉ |
| Stellar Mass | 0.6600 M☉ |
| Bolometric Luminosity | 0.121 L☉ |
| Metallicity [Fe/H] | -0.210 dex |
| Stellar Age | 2.400 Gyr |
| Apparent Magnitude | V: 15.617 · G: 15.418 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.136000 AU |
| Orbital Period | 22.929 days |
| Mean Orbital Velocity | 64.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 89.1500° |
| Mean Bulk Density | 3.36 g/cm³ (16.9 km/s vesc) |
| Insolation Flux | 8.6960 S⊕ (~11,835 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1690.200 LY (518.204 pc) |