WASP-47 c

Astrophysical Synthesis & Habitability Characterization

WASP-47 c is a confirmed gas giant exoplanet orbiting the star WASP-47, located approximately 863.6 light-years (264.78 parsecs) from the Solar System. First announced in 2015 by La Silla 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 447 Earth masses (1.41 M♃), while its physical transit radius has not yet been geometrically observed.

In its orbital architecture around WASP-47, WASP-47 c completes one full revolution every 589.57 Earth days (1.61Julian years) at a semi-major axis of 1.393 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 25.7 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.264, swinging from 1.0252 AU at periapsis out to 1.7608 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.

✓ Classified as a Temperate Habitable Zone Candidate.

With an estimated equilibrium temperature of 247 K (-26°C / -15°F) and an incident stellar irradiance of 0.55 S⊕ (~747 W/m²), WASP-47 c orbits within the empirical circumstellar habitable zone where a rocky surface under sufficient atmospheric pressure can maintain liquid surface water.

The host star WASP-47 is classified as a solar-type yellow star of spectral type G9 with an effective photospheric temperature of 5,565 K, a radius of 1.156 R☉, a mass of 1.058 M☉, an estimated bolometric luminosity of 1.15 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.5 Gyr and a metallicity of [Fe/H] = 0.43 dex (metal-rich relative to the Sun). From Earth, WASP-47 shines at apparent V-band magnitude 11.936 (faint and requiring research-grade or CCD telescopic photometry) in the Southern celestial hemisphere. The WASP-47 system is a multi-planet architecture hosting 4 confirmed worlds, with WASP-47 c sharing its stellar neighborhood alongside WASP-47 e, WASP-47 b, WASP-47 d.

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