K2-172 b
Astrophysical Synthesis & Habitability Characterization
K2-172 b is a confirmed super-earth exoplanet orbiting the star K2-172, located approximately 814.5 light-years (249.74 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0309% across the stellar disk), this world measures 1.666 Earth radii and has a measured mass of 3.42 Earth masses. Combining its mass and radius yields a mean bulk density of 4.08 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 K2-172, K2-172 b completes one full revolution every 14.317 Earth days.
ℹ️ Thermal & Atmospheric Regime: Current photometric and spectroscopic constraints for K2-172 b place it outside the conservative habitable zone definition pending further atmospheric characterization.
The host star K2-172 is classified as a stellar host with an effective photospheric temperature of 5,569 K, a radius of 0.8689 R☉, a mass of 0.9344 M☉, an estimated bolometric luminosity of 0.652 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.06 dex (near-solar heavy-element abundance). From Earth, K2-172 shines at apparent V-band magnitude 12.5 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The K2-172 system is a multi-planet architecture hosting 2 confirmed worlds, with K2-172 b sharing its stellar neighborhood alongside K2-172 c.
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 | K2-172 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,569 K |
| Stellar Radius | 0.8689 R☉ |
| Stellar Mass | 0.9344 M☉ |
| Bolometric Luminosity | 0.652 L☉ |
| Metallicity [Fe/H] | -0.060 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.500 · G: 12.281 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 14.317 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 88.9135° |
| Mean Bulk Density | 4.08 g/cm³ (16 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 814.500 LY (249.742 pc) |