HD 122562 c

Astrophysical Synthesis & Habitability Characterization

HD 122562 c is a confirmed gas giant exoplanet orbiting the star HD 122562, located approximately 173.7 light-years (53.25 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 10.1 Earth radii (0.9 Jupiter radii) and has a measured mass of 73.101 Earth masses (0.23 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.39 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.72 g⊕ (7.06 m/s²), and an escape velocity of 30.1 km/s.

In its orbital architecture around HD 122562, HD 122562 c completes one full revolution every 84.963 Earth days at a semi-major axis of 0.406 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 52 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.228 carries the world between 0.3134 AU at periapsis and 0.4986 AU at apoapsis, driving measurable seasonal insolation cycles.

⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 552 K (+279°C / +534°F) and receiving 15.49 S⊕ (~21,077 W/m²), HD 122562 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.

The host star HD 122562 is classified as a stellar host with an effective photospheric temperature of 4,956 K, a radius of 2.1663 R☉, a mass of 1.241 M☉, an estimated bolometric luminosity of 2.54 L☉. From Earth, HD 122562 shines at apparent V-band magnitude 7.659 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere.

Discovery Facility: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).