HD 41004 A b

Astrophysical Synthesis & Habitability Characterization

HD 41004 A b is a confirmed gas giant exoplanet orbiting the star HD 41004 A, located approximately 119.7 light-years (36.69 parsecs) from the Solar System. First announced in 2004 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.2 Earth radii (1.18 Jupiter radii) and has a measured mass of 807.25 Earth masses (2.54 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.94 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.63 g⊕ (45.4 m/s²), and an escape velocity of 87.5 km/s.

In its orbital architecture around HD 41004 A, HD 41004 A b completes one full revolution every 963 Earth days (2.64Julian years). The planet follows a highly eccentric trajectory (e = 0.74), pointing to past dynamical scattering or secular gravitational perturbations.

☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.200 R⊕, HD 41004 A b exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.

The host star HD 41004 A is classified as an orange K-type star of spectral type K1/K2 V with an effective photospheric temperature of 5,310 K, a radius of 0.85 R☉, a mass of 0.95 M☉, an estimated bolometric luminosity of 0.515 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.22 Gyr and a metallicity of [Fe/H] = 0.23 dex (metal-rich relative to the Sun). From Earth, HD 41004 A shines at apparent V-band magnitude 8.65 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.

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