Kepler-1291 b
Astrophysical Synthesis & Habitability Characterization
Kepler-1291 b is a confirmed super-earth exoplanet orbiting the star Kepler-1291, located approximately 2926.8 light-years (897.35 parsecs) from the Solar System. First announced in 2016 by Kepler using the Transit detection technique (producing an estimated primary transit depth of 0.0362% across the stellar disk), this world measures 1.66 Earth radii and has a measured mass of 3.39 Earth masses. Combining its mass and radius yields a mean bulk density of 4.09 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.23 g⊕ (12.06 m/s²), and an escape velocity of 16 km/s.
In its orbital architecture around Kepler-1291, Kepler-1291 b completes one full revolution every 8.63 Earth days at a semi-major axis of 0.0779 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 98.2 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 739 K (+466°C / +871°F) and receiving 62.82 S⊕ (~85,502 W/m²), Kepler-1291 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star Kepler-1291 is classified as a stellar host with an effective photospheric temperature of 5,216 K, a radius of 0.8 R☉, a mass of 0.84 M☉, an estimated bolometric luminosity of 0.425 L☉. Stellar evolution modeling indicates an estimated stellar age of 4.9 Gyr and a metallicity of [Fe/H] = -0.04 dex (near-solar heavy-element abundance). From Earth, Kepler-1291 shines at apparent V-band magnitude 16.261 (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-1291 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,216 K |
| Stellar Radius | 0.8000 R☉ |
| Stellar Mass | 0.8400 M☉ |
| Bolometric Luminosity | 0.425 L☉ |
| Metallicity [Fe/H] | -0.040 dex |
| Stellar Age | 4.900 Gyr |
| Apparent Magnitude | V: 16.261 · G: 15.883 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.077900 AU |
| Orbital Period | 8.63 days |
| Mean Orbital Velocity | 98.2 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | 88.0300° |
| Mean Bulk Density | 4.09 g/cm³ (16 km/s vesc) |
| Insolation Flux | 62.8230 S⊕ (~85,502 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 2926.800 LY (897.352 pc) |