HD 33844 c
Astrophysical Synthesis & Habitability Characterization
HD 33844 c is a confirmed gas giant exoplanet orbiting the star HD 33844, located approximately 345 light-years (105.78 parsecs) from the Solar System. First announced in 2015 by Anglo-Australian Telescope using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.5 Earth radii (1.2 Jupiter radii) and has a measured mass of 556.203 Earth masses (1.75 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 3.05 g⊕ (29.91 m/s²), and an escape velocity of 71.8 km/s.
In its orbital architecture around HD 33844, HD 33844 c completes one full revolution every 916 Earth days (2.51Julian years) at a semi-major axis of 2.24 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 26.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.13 carries the world between 1.9488 AU at periapsis and 2.5312 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 360 K (+87°C / +189°F) and receiving 2.81 S⊕ (~3,825 W/m²), HD 33844 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 33844 is classified as an orange K-type star of spectral type K0 III with an effective photospheric temperature of 4,861 K, a radius of 5.29 R☉, a mass of 1.78 M☉, an estimated bolometric luminosity of 14.019 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.88 Gyr and a metallicity of [Fe/H] = 0.27 dex (metal-rich relative to the Sun). From Earth, HD 33844 shines at apparent V-band magnitude 7.29 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 33844 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 33844 c sharing its stellar neighborhood alongside HD 33844 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: Anglo-Australian Telescope · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 33844 |
| Spectral Type | K0 III |
| Effective Temp (Teff) | 4,861 K |
| Stellar Radius | 5.2900 R☉ |
| Stellar Mass | 1.7800 M☉ |
| Bolometric Luminosity | 14.019 L☉ |
| Metallicity [Fe/H] | 0.270 dex |
| Stellar Age | 1.880 Gyr |
| Apparent Magnitude | V: 7.290 · G: 7.012 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 2.240000 AU |
| Orbital Period | 916 days |
| Mean Orbital Velocity | 26.6 km/s |
| Orbital Eccentricity (e) | 0.13000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.25 g/cm³ (71.8 km/s vesc) |
| Insolation Flux | 2.8101 S⊕ (~3,825 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 345.000 LY (105.779 pc) |