K2-35 b
Astrophysical Synthesis & Habitability Characterization
K2-35 b is a confirmed super-earth exoplanet orbiting the star K2-35, located approximately 823.9 light-years (252.6 parsecs) from the Solar System. First announced in 2016 by K2 using the Transit detection technique (producing an estimated primary transit depth of 0.0381% across the stellar disk), this world measures 1.32 Earth radii and has a measured mass of 2.3 Earth masses. Combining its mass and radius yields a mean bulk density of 5.51 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 1.32 g⊕ (12.94 m/s²), and an escape velocity of 14.8 km/s.
In its orbital architecture around K2-35, K2-35 b completes one full revolution every 2.4 Earth days at a semi-major axis of 0.031 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 140.5 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 0.027 AU at periapsis and 0.035 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 979 K (+706°C / +1303°F) and receiving 211.00 S⊕ (~287,171 W/m²), K2-35 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-35 is classified as an orange K-type star of spectral type K4 V with an effective photospheric temperature of 4,403 K, a radius of 0.6196 R☉, a mass of 0.702 M☉, an estimated bolometric luminosity of 0.129 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.04 dex (near-solar heavy-element abundance). From Earth, K2-35 shines at apparent V-band magnitude 14.166 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The K2-35 system is a multi-planet architecture hosting 2 confirmed worlds, with K2-35 b sharing its stellar neighborhood alongside K2-35 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 | K2-35 |
| Spectral Type | K4 V |
| Effective Temp (Teff) | 4,403 K |
| Stellar Radius | 0.6196 R☉ |
| Stellar Mass | 0.7020 M☉ |
| Bolometric Luminosity | 0.129 L☉ |
| Metallicity [Fe/H] | 0.040 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 14.166 · G: 13.915 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.031000 AU |
| Orbital Period | 2.4 days |
| Mean Orbital Velocity | 140.5 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | 88.9800° |
| Mean Bulk Density | 5.51 g/cm³ (14.8 km/s vesc) |
| Insolation Flux | 211.0000 S⊕ (~287,171 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 823.900 LY (252.596 pc) |