K2-419 A b
Astrophysical Synthesis & Habitability Characterization
K2-419 A b is a confirmed gas giant exoplanet orbiting the star K2-419 A, located approximately 876.3 light-years (268.69 parsecs) from the Solar System. First announced in 2024 by K2 using the Transit detection technique (producing an estimated primary transit depth of 3.1963% across the stellar disk), this world measures 10.55 Earth radii (0.94 Jupiter radii) and has a measured mass of 196 Earth masses (0.62 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.92 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.76 g⊕ (17.26 m/s²), and an escape velocity of 48.2 km/s.
In its orbital architecture around K2-419 A, K2-419 A b completes one full revolution every 20.358 Earth days at a semi-major axis of 0.1208 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 64.6 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.042 (ranging from 0.1157 AU at periapsis to 0.1259 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 377 K (+104°C / +219°F) and receiving 3.30 S⊕ (~4,491 W/m²), K2-419 A b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star K2-419 A is classified as a stellar host with an effective photospheric temperature of 3,711 K, a radius of 0.541 R☉, a mass of 0.562 M☉, an estimated bolometric luminosity of 0.05 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.4 Gyr and a metallicity of [Fe/H] = -0.11 dex (metal-poor relative to the Sun). From Earth, K2-419 A shines at apparent V-band magnitude 16.52 (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 | K2-419 A |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 3,711 K |
| Stellar Radius | 0.5410 R☉ |
| Stellar Mass | 0.5620 M☉ |
| Bolometric Luminosity | 0.05 L☉ |
| Metallicity [Fe/H] | -0.110 dex |
| Stellar Age | 7.400 Gyr |
| Apparent Magnitude | V: 16.520 · G: 15.734 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.120800 AU |
| Orbital Period | 20.358 days |
| Mean Orbital Velocity | 64.6 km/s |
| Orbital Eccentricity (e) | 0.04200 |
| Orbital Inclination (i) | 89.5400° |
| Mean Bulk Density | 0.92 g/cm³ (48.2 km/s vesc) |
| Insolation Flux | 3.3000 S⊕ (~4,491 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 876.300 LY (268.685 pc) |