HD 160691 c

Astrophysical Synthesis & Habitability Characterization

HD 160691 c is a confirmed gas giant exoplanet orbiting the star HD 160691, located approximately 50.9 light-years (15.6 parsecs) from the Solar System. First announced in 2004 by Anglo-Australian Telescope 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 1398.445 Earth masses (4.4 M♃), while its physical transit radius has not yet been geometrically observed.

In its orbital architecture around HD 160691, HD 160691 c completes one full revolution every 3947 Earth days (10.81Julian years) at a semi-major axis of 4.17 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 11.5 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.039 (ranging from 4.0074 AU at periapsis to 4.3326 AU at apoapsis), the planet experiences minimal orbital distance variation.

❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 157 K (-116°C / -177°F) and an incident flux of 0.11 S⊕ (~149 W/m²), surface water and volatile species on HD 160691 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.

The host star HD 160691 is classified as a solar-type yellow star of spectral type G3 IV-V with an effective photospheric temperature of 5,773 K, a radius of 1.33 R☉, a mass of 1.13 M☉, an estimated bolometric luminosity of 1.763 L☉. Stellar evolution modeling indicates an estimated stellar age of 5.7 Gyr and a metallicity of [Fe/H] = 0.28 dex (metal-rich relative to the Sun). From Earth, HD 160691 shines at apparent V-band magnitude 5.12 (visible to the unaided human eye under dark skies) in the Southern celestial hemisphere. The HD 160691 system is a multi-planet architecture hosting 4 confirmed worlds, with HD 160691 c sharing its stellar neighborhood alongside HD 160691 d, HD 160691 e, HD 160691 b.

Discovery Facility: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).