GJ 508.2 b

Astrophysical Synthesis & Habitability Characterization

GJ 508.2 b is a confirmed gas giant exoplanet orbiting the star GJ 508.2, located approximately 54.3 light-years (16.64 parsecs) from the Solar System. First announced in 2025 by Calar Alto Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world has a minimum or true mass of 587.983 Earth masses (1.85 M♃), while its physical transit radius has not yet been geometrically observed.

In its orbital architecture around GJ 508.2, GJ 508.2 b completes one full revolution every 5300 Earth days (14.51Julian years) at a semi-major axis of 4.85 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 10 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.27, swinging from 3.5405 AU at periapsis out to 6.1595 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.

❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 59 K (-214°C / -353°F) and an incident flux of 0.00 S⊕ (~3 W/m²), surface water and volatile species on GJ 508.2 b would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.

The host star GJ 508.2 is classified as a low-mass red dwarf of spectral type M1.0 V with an effective photospheric temperature of 3,720 K, a radius of 0.53 R☉, a mass of 0.54 M☉, an estimated bolometric luminosity of 0.048 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.15 dex (metal-poor relative to the Sun). From Earth, GJ 508.2 shines at apparent V-band magnitude 10.61 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

Discovery Facility: Calar Alto Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).