HD 213472 b
Astrophysical Synthesis & Habitability Characterization
HD 213472 b is a confirmed gas giant exoplanet orbiting the star HD 213472, located approximately 210.2 light-years (64.45 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.1 Earth radii (1.17 Jupiter radii) and has a measured mass of 1112.399 Earth masses (3.5 Jupiter masses). Combining its mass and radius yields a mean bulk density of 2.73 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 6.48 g⊕ (63.55 m/s²), and an escape velocity of 103.1 km/s.
In its orbital architecture around HD 213472, HD 213472 b completes one full revolution every 17000 Earth days (46.54Julian years) at a semi-major axis of 13 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 8.3 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.53, swinging from 6.11 AU at periapsis out to 19.89 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 92 K (-181°C / -294°F) and an incident flux of 0.01 S⊕ (~16 W/m²), surface water and volatile species on HD 213472 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 213472 is classified as a stellar host with an effective photospheric temperature of 5,730 K, a radius of 1.4339 R☉, a mass of 1.0481 M☉, an estimated bolometric luminosity of 1.989 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.125 dex (metal-rich relative to the Sun). From Earth, HD 213472 shines at apparent V-band magnitude 8.17 (accessible to binoculars and small amateur telescopes) 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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 213472 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,730 K |
| Stellar Radius | 1.4339 R☉ |
| Stellar Mass | 1.0481 M☉ |
| Bolometric Luminosity | 1.989 L☉ |
| Metallicity [Fe/H] | 0.125 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 8.170 · G: 8.012 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 13.000000 AU |
| Orbital Period | 17000 days |
| Mean Orbital Velocity | 8.3 km/s |
| Orbital Eccentricity (e) | 0.53000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.73 g/cm³ (103.1 km/s vesc) |
| Insolation Flux | 0.0114 S⊕ (~16 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 210.200 LY (64.453 pc) |