HD 210193 b
Astrophysical Synthesis & Habitability Characterization
HD 210193 b is a confirmed gas giant exoplanet orbiting the star HD 210193, located approximately 137.6 light-years (42.2 parsecs) from the Solar System. First announced in 2019 by Las Campanas Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 14.3 Earth radii (1.28 Jupiter radii) and has a measured mass of 153.1 Earth masses (0.48 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.29 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.75 g⊕ (7.35 m/s²), and an escape velocity of 36.6 km/s.
In its orbital architecture around HD 210193, HD 210193 b completes one full revolution every 649.918 Earth days (1.78Julian years) at a semi-major axis of 1.487 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 24.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 1.1301 AU at periapsis and 1.8439 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 14.300 R⊕, HD 210193 b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HD 210193 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 5,790 K, a radius of 1.0597 R☉, a mass of 1.04 M☉, an estimated bolometric luminosity of 1.132 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.13 dex (metal-rich relative to the Sun). From Earth, HD 210193 shines at apparent V-band magnitude 7.83 (accessible to binoculars and small amateur telescopes) in the Southern 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: Las Campanas Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 210193 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 5,790 K |
| Stellar Radius | 1.0597 R☉ |
| Stellar Mass | 1.0400 M☉ |
| Bolometric Luminosity | 1.132 L☉ |
| Metallicity [Fe/H] | 0.130 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.830 · G: 7.669 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.487000 AU |
| Orbital Period | 649.918 days |
| Mean Orbital Velocity | 24.9 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.29 g/cm³ (36.6 km/s vesc) |
| Insolation Flux | 0.5142 S⊕ (~700 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 137.600 LY (42.203 pc) |