HD 24040 c
Astrophysical Synthesis & Habitability Characterization
HD 24040 c is a confirmed gas giant exoplanet orbiting the star HD 24040, located approximately 152.1 light-years (46.62 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 9.35 Earth radii (0.83 Jupiter radii) and has a measured mass of 63.884 Earth masses (0.2 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.43 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.73 g⊕ (7.16 m/s²), and an escape velocity of 29.2 km/s.
In its orbital architecture around HD 24040, HD 24040 c completes one full revolution every 515.4 Earth days (1.41Julian years) at a semi-major axis of 1.3 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 27.4 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.11 carries the world between 1.157 AU at periapsis and 1.443 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 9.350 R⊕, HD 24040 c 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 24040 is classified as a solar-type yellow star of spectral type G0 V with an effective photospheric temperature of 5,776 K, a radius of 1.3873 R☉, a mass of 1.1039 M☉, an estimated bolometric luminosity of 1.922 L☉. Stellar evolution modeling indicates an estimated stellar age of 6.68 Gyr and a metallicity of [Fe/H] = 0.197 dex (metal-rich relative to the Sun). From Earth, HD 24040 shines at apparent V-band magnitude 7.515 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 24040 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 24040 c sharing its stellar neighborhood alongside HD 24040 b.
Methodology: Computed using the Schulze-Makuch et al. (2011) weighted metric comparing physical interior (radius, estimated density) and surface thermal regime (escape velocity, equilibrium temperature).
Discovery Facility: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 24040 |
| Spectral Type | G0 V |
| Effective Temp (Teff) | 5,776 K |
| Stellar Radius | 1.3873 R☉ |
| Stellar Mass | 1.1039 M☉ |
| Bolometric Luminosity | 1.922 L☉ |
| Metallicity [Fe/H] | 0.197 dex |
| Stellar Age | 6.680 Gyr |
| Apparent Magnitude | V: 7.515 · G: 7.335 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.300000 AU |
| Orbital Period | 515.4 days |
| Mean Orbital Velocity | 27.4 km/s |
| Orbital Eccentricity (e) | 0.11000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.43 g/cm³ (29.2 km/s vesc) |
| Insolation Flux | 1.1163 S⊕ (~1,519 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 152.100 LY (46.622 pc) |