GJ 1151 c

Astrophysical Synthesis & Habitability Characterization

GJ 1151 c is a confirmed sub-neptune exoplanet orbiting the star GJ 1151, located approximately 26.2 light-years (8.04 parsecs) from the Solar System. First announced in 2023 by Multiple Facilities using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 3.25 Earth radii (0.29 Jupiter radii) and has a measured mass of 10.62 Earth masses. Combining its mass and radius yields a mean bulk density of 1.71 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.01 g⊕ (9.9 m/s²), and an escape velocity of 20.2 km/s.

In its orbital architecture around GJ 1151, GJ 1151 c completes one full revolution every 389.7 Earth days (1.07Julian years) at a semi-major axis of 0.5714 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 16 km/s (compared to Earth's 29.8 km/s).

❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 88 K (-185°C / -301°F) and an incident flux of 0.01 S⊕ (~14 W/m²), surface water and volatile species on GJ 1151 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.

The host star GJ 1151 is classified as a low-mass red dwarf of spectral type M 4.5V with an effective photospheric temperature of 3,280 K, a radius of 0.1781 R☉, a mass of 0.1639 M☉, an estimated bolometric luminosity of 0.00329 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.12 dex (metal-poor relative to the Sun). From Earth, GJ 1151 shines at apparent V-band magnitude 13.76 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere.

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