Kepler-276 c
Astrophysical Synthesis & Habitability Characterization
Kepler-276 c is a confirmed sub-neptune exoplanet orbiting the star Kepler-276, located approximately 3734 light-years (1144.86 parsecs) from the Solar System. First announced in 2013 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0666% across the stellar disk), this world measures 2.9 Earth radii and has a measured mass of 16.6 Earth masses. Combining its mass and radius yields a mean bulk density of 3.75 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.97 g⊕ (19.32 m/s²), and an escape velocity of 26.8 km/s.
In its orbital architecture around Kepler-276, Kepler-276 c completes one full revolution every 31.884 Earth days at a semi-major axis of 0.18619 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 63.5 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 563 K (+290°C / +554°F) and receiving 19.79 S⊕ (~26,938 W/m²), Kepler-276 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-276 is classified as a stellar host with an effective photospheric temperature of 5,693 K, a radius of 1.03 R☉, a mass of 1.1 M☉, an estimated bolometric luminosity of 1 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.4 Gyr and a metallicity of [Fe/H] = -0.29 dex (metal-poor relative to the Sun). From Earth, Kepler-276 shines at apparent V-band magnitude 15.481 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The Kepler-276 system is a multi-planet architecture hosting 3 confirmed worlds, with Kepler-276 c sharing its stellar neighborhood alongside Kepler-276 b, Kepler-276 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-276 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,693 K |
| Stellar Radius | 1.0300 R☉ |
| Stellar Mass | 1.1000 M☉ |
| Bolometric Luminosity | 1 L☉ |
| Metallicity [Fe/H] | -0.290 dex |
| Stellar Age | 0.400 Gyr |
| Apparent Magnitude | V: 15.481 · G: 15.365 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.186190 AU |
| Orbital Period | 31.884 days |
| Mean Orbital Velocity | 63.5 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 86.9200° |
| Mean Bulk Density | 3.75 g/cm³ (26.8 km/s vesc) |
| Insolation Flux | 19.7930 S⊕ (~26,938 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 3734.000 LY (1144.860 pc) |