HD 13724 c
Astrophysical Synthesis & Habitability Characterization
HD 13724 c is a confirmed gas giant exoplanet orbiting the star HD 13724, located approximately 141.8 light-years (43.47 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 8.18 Earth radii (0.73 Jupiter radii) and has a measured mass of 50.853 Earth masses (0.16 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.51 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.76 g⊕ (7.45 m/s²), and an escape velocity of 27.9 km/s.
In its orbital architecture around HD 13724, HD 13724 c completes one full revolution every 142.229 Earth days at a semi-major axis of 0.534 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 40.8 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.651, swinging from 0.1864 AU at periapsis out to 0.8816 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 393 K (+120°C / +248°F) and receiving 3.98 S⊕ (~5,413 W/m²), HD 13724 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 13724 is classified as a stellar host with an effective photospheric temperature of 5,835 K, a radius of 1.042 R☉, a mass of 1.004 M☉, an estimated bolometric luminosity of 1.129 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.217 dex (metal-rich relative to the Sun). From Earth, HD 13724 shines at apparent V-band magnitude 7.89 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere.
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 13724 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,835 K |
| Stellar Radius | 1.0420 R☉ |
| Stellar Mass | 1.0040 M☉ |
| Bolometric Luminosity | 1.129 L☉ |
| Metallicity [Fe/H] | 0.217 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 7.890 · G: 7.730 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.534000 AU |
| Orbital Period | 142.229 days |
| Mean Orbital Velocity | 40.8 km/s |
| Orbital Eccentricity (e) | 0.65100 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.51 g/cm³ (27.9 km/s vesc) |
| Insolation Flux | 3.9773 S⊕ (~5,413 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 141.800 LY (43.465 pc) |