K2-177 b
Astrophysical Synthesis & Habitability Characterization
K2-177 b is a confirmed sub-neptune exoplanet orbiting the star K2-177, located approximately 1605.2 light-years (492.17 parsecs) from the Solar System. First announced in 2018 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0256% across the stellar disk), this world measures 2.116 Earth radii and has a measured mass of 5.13 Earth masses. Combining its mass and radius yields a mean bulk density of 2.99 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.15 g⊕ (11.28 m/s²), and an escape velocity of 17.4 km/s.
In its orbital architecture around K2-177, K2-177 b completes one full revolution every 14.155 Earth days.
ℹ️ Thermal & Atmospheric Regime: Current photometric and spectroscopic constraints for K2-177 b place it outside the conservative habitable zone definition pending further atmospheric characterization.
The host star K2-177 is classified as a stellar host with an effective photospheric temperature of 6,063 K, a radius of 1.2136 R☉, a mass of 1.2105 M☉, an estimated bolometric luminosity of 1.786 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.41 dex (metal-rich relative to the Sun). From Earth, K2-177 shines at apparent V-band magnitude 12.681 (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 | K2-177 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 6,063 K |
| Stellar Radius | 1.2136 R☉ |
| Stellar Mass | 1.2105 M☉ |
| Bolometric Luminosity | 1.786 L☉ |
| Metallicity [Fe/H] | 0.410 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 12.681 · G: 12.422 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | — |
| Orbital Period | 14.155 days |
| Orbital Eccentricity (e) | Circular (0.00) |
| Orbital Inclination (i) | 87.2196° |
| Mean Bulk Density | 2.99 g/cm³ (17.4 km/s vesc) |
| Insolation Flux | — |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1605.200 LY (492.167 pc) |