HD 72490 b
Astrophysical Synthesis & Habitability Characterization
HD 72490 b is a confirmed gas giant exoplanet orbiting the star HD 72490, located approximately 412.1 light-years (126.34 parsecs) from the Solar System. First announced in 2018 by W. M. Keck Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 561.923 Earth masses (1.77 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.26 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.08 g⊕ (30.2 m/s²), and an escape velocity of 72.2 km/s.
In its orbital architecture around HD 72490, HD 72490 b completes one full revolution every 858 Earth days (2.35Julian years) at a semi-major axis of 1.88 AU (corresponding to the middle-system regime between Mars at 1.52 AU and Jupiter at 5.20 AU). Its mean orbital velocity is approximately 23.8 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.124 carries the world between 1.6469 AU at periapsis and 2.1131 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 386 K (+113°C / +235°F) and receiving 3.49 S⊕ (~4,749 W/m²), HD 72490 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 72490 is classified as a solar-type yellow star of spectral type G5 with an effective photospheric temperature of 4,934 K, a radius of 4.96 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 13.081 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.13 dex (metal-poor relative to the Sun). From Earth, HD 72490 shines at apparent V-band magnitude 7.82 (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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 72490 |
| Spectral Type | G5 |
| Effective Temp (Teff) | 4,934 K |
| Stellar Radius | 4.9600 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 13.081 L☉ |
| Metallicity [Fe/H] | -0.130 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.820 · G: 7.574 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.880000 AU |
| Orbital Period | 858 days |
| Mean Orbital Velocity | 23.8 km/s |
| Orbital Eccentricity (e) | 0.12400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.26 g/cm³ (72.2 km/s vesc) |
| Insolation Flux | 3.4894 S⊕ (~4,749 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 412.100 LY (126.339 pc) |