24 Sex c
Astrophysical Synthesis & Habitability Characterization
24 Sex c is a confirmed gas giant exoplanet orbiting the star 24 Sex, located approximately 235.1 light-years (72.07 parsecs) from the Solar System. First announced in 2010 by Lick Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.9 Earth radii (1.24 Jupiter radii) and has a measured mass of 273.32 Earth masses (0.86 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.56 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.41 g⊕ (13.83 m/s²), and an escape velocity of 49.6 km/s.
In its orbital architecture around 24 Sex, 24 Sex c completes one full revolution every 883 Earth days (2.42Julian years) at a semi-major axis of 2.08 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 25.6 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.29, swinging from 1.4768 AU at periapsis out to 2.6832 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 377 K (+104°C / +219°F) and receiving 3.37 S⊕ (~4,589 W/m²), 24 Sex c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star 24 Sex is classified as an orange K-type star of spectral type K0 IV with an effective photospheric temperature of 5,098 K, a radius of 4.9 R☉, a mass of 1.54 M☉, an estimated bolometric luminosity of 14.551 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.7 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, 24 Sex shines at apparent V-band magnitude 6.454 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The 24 Sex system is a multi-planet architecture hosting 2 confirmed worlds, with 24 Sex c sharing its stellar neighborhood alongside 24 Sex 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: Lick Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | 24 Sex |
| Spectral Type | K0 IV |
| Effective Temp (Teff) | 5,098 K |
| Stellar Radius | 4.9000 R☉ |
| Stellar Mass | 1.5400 M☉ |
| Bolometric Luminosity | 14.551 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 2.700 Gyr |
| Apparent Magnitude | V: 6.454 · G: 6.204 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.080000 AU |
| Orbital Period | 883 days |
| Mean Orbital Velocity | 25.6 km/s |
| Orbital Eccentricity (e) | 0.29000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.56 g/cm³ (49.6 km/s vesc) |
| Insolation Flux | 3.3719 S⊕ (~4,589 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 235.100 LY (72.069 pc) |