HD 33142 c
Astrophysical Synthesis & Habitability Characterization
HD 33142 c is a confirmed gas giant exoplanet orbiting the star HD 33142, located approximately 395.9 light-years (121.38 parsecs) from the Solar System. First announced in 2016 by W. M. Keck 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 282.867 Earth masses (0.89 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.58 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 1.46 g⊕ (14.32 m/s²), and an escape velocity of 50.5 km/s.
In its orbital architecture around HD 33142, HD 33142 c completes one full revolution every 810.2 Earth days (2.22Julian years) at a semi-major axis of 1.955 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 26.3 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.081 carries the world between 1.7966 AU at periapsis and 2.1134 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 354 K (+81°C / +178°F) and receiving 2.62 S⊕ (~3,564 W/m²), HD 33142 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 33142 is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 5,025 K, a radius of 4.17 R☉, a mass of 1.52 M☉, an estimated bolometric luminosity of 9.947 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.72 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, HD 33142 shines at apparent V-band magnitude 7.96 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 33142 system is a multi-planet architecture hosting 3 confirmed worlds, with HD 33142 c sharing its stellar neighborhood alongside HD 33142 d, HD 33142 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: W. M. Keck Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 33142 |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 5,025 K |
| Stellar Radius | 4.1700 R☉ |
| Stellar Mass | 1.5200 M☉ |
| Bolometric Luminosity | 9.947 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 2.720 Gyr |
| Apparent Magnitude | V: 7.960 · G: 7.713 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.955000 AU |
| Orbital Period | 810.2 days |
| Mean Orbital Velocity | 26.3 km/s |
| Orbital Eccentricity (e) | 0.08100 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.58 g/cm³ (50.5 km/s vesc) |
| Insolation Flux | 2.6190 S⊕ (~3,564 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 395.900 LY (121.375 pc) |