K2-133 e
Astrophysical Synthesis & Habitability Characterization
K2-133 e is a confirmed super-earth exoplanet orbiting the star K2-133, located approximately 245.2 light-years (75.17 parsecs) from the Solar System. First announced in 2019 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.1215% across the stellar disk), this world measures 1.73 Earth radii and has a measured mass of 3.64 Earth masses. Combining its mass and radius yields a mean bulk density of 3.88 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.22 g⊕ (11.96 m/s²), and an escape velocity of 16.2 km/s.
In its orbital architecture around K2-133, K2-133 e completes one full revolution every 26.584 Earth days at a semi-major axis of 0.1346 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 55.1 km/s (compared to Earth's 29.8 km/s).
✓ Classified as a Temperate Habitable Zone Candidate.
With an estimated equilibrium temperature of 296 K (+23°C / +73°F) and an incident stellar irradiance of 1.80 S⊕ (~2,450 W/m²), K2-133 e orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.
The host star K2-133 is classified as a low-mass red dwarf of spectral type M1.5 V with an effective photospheric temperature of 3,655 K, a radius of 0.455 R☉, a mass of 0.461 M☉, an estimated bolometric luminosity of 0.033 L☉. From Earth, K2-133 shines at apparent V-band magnitude 14.073 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The K2-133 system is a multi-planet architecture hosting 4 confirmed worlds, with K2-133 e sharing its stellar neighborhood alongside K2-133 b, K2-133 c, K2-133 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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | K2-133 |
| Spectral Type | M1.5 V |
| Effective Temp (Teff) | 3,655 K |
| Stellar Radius | 0.4550 R☉ |
| Stellar Mass | 0.4610 M☉ |
| Bolometric Luminosity | 0.033 L☉ |
| Metallicity [Fe/H] | — |
| Stellar Age | — |
| Apparent Magnitude | V: 14.073 · G: 13.325 |
| System Architecture | 1 Star, 4 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.134600 AU |
| Orbital Period | 26.584 days |
| Mean Orbital Velocity | 55.1 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 89.1640° |
| Mean Bulk Density | 3.88 g/cm³ (16.2 km/s vesc) |
| Insolation Flux | 1.8000 S⊕ (~2,450 W/m²) |
| Habitable Zone Status | ★ Temperate Zone |
| Celestial Distance | 245.200 LY (75.170 pc) |