K2-149 b
Astrophysical Synthesis & Habitability Characterization
K2-149 b is a confirmed super-earth exoplanet orbiting the star K2-149, located approximately 403.4 light-years (123.68 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0701% across the stellar disk), this world measures 1.64 Earth radii and has a measured mass of 3.33 Earth masses. Combining its mass and radius yields a mean bulk density of 4.16 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.24 g⊕ (12.16 m/s²), and an escape velocity of 15.9 km/s.
In its orbital architecture around K2-149, K2-149 b completes one full revolution every 11.332 Earth days at a semi-major axis of 0.083 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 79.7 km/s (compared to Earth's 29.8 km/s).
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 472 K (+199°C / +390°F) and receiving 7.00 S⊕ (~9,527 W/m²), K2-149 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-149 is classified as a low-mass red dwarf of spectral type M1.0 V with an effective photospheric temperature of 3,745 K, a radius of 0.568 R☉, a mass of 0.595 M☉, an estimated bolometric luminosity of 0.057 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, K2-149 shines at apparent V-band magnitude 14.543 (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: K2 · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | K2-149 |
| Spectral Type | M1.0 V |
| Effective Temp (Teff) | 3,745 K |
| Stellar Radius | 0.5680 R☉ |
| Stellar Mass | 0.5950 M☉ |
| Bolometric Luminosity | 0.057 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.543 · G: 13.780 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.083000 AU |
| Orbital Period | 11.332 days |
| Mean Orbital Velocity | 79.7 km/s |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 4.16 g/cm³ (15.9 km/s vesc) |
| Insolation Flux | 7.0000 S⊕ (~9,527 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 403.400 LY (123.676 pc) |