HAT-P-44 c
Astrophysical Synthesis & Habitability Characterization
HAT-P-44 c is a confirmed gas giant exoplanet orbiting the star HAT-P-44, located approximately 1134.5 light-years (347.85 parsecs) from the Solar System. First announced in 2014 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 Earth radii (1.16 Jupiter radii) and has a measured mass of 1271.3 Earth masses (4 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.19 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 7.52 g⊕ (73.75 m/s²), and an escape velocity of 110.6 km/s.
In its orbital architecture around HAT-P-44, HAT-P-44 c completes one full revolution every 872.2 Earth days (2.39Julian years) at a semi-major axis of 1.752 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 21.9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.494, swinging from 0.8865 AU at periapsis out to 2.6175 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 13.000 R⊕, HAT-P-44 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 HAT-P-44 is classified as a stellar host with an effective photospheric temperature of 5,295 K, a radius of 0.949 R☉, a mass of 0.942 M☉, an estimated bolometric luminosity of 0.635 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.5 Gyr and a metallicity of [Fe/H] = 0.33 dex (metal-rich relative to the Sun). From Earth, HAT-P-44 shines at apparent V-band magnitude 13.225 (faint and requiring research-grade or CCD telescopic photometry) in the Northern celestial hemisphere. The HAT-P-44 system is a multi-planet architecture hosting 2 confirmed worlds, with HAT-P-44 c sharing its stellar neighborhood alongside HAT-P-44 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 | HAT-P-44 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,295 K |
| Stellar Radius | 0.9490 R☉ |
| Stellar Mass | 0.9420 M☉ |
| Bolometric Luminosity | 0.635 L☉ |
| Metallicity [Fe/H] | 0.330 dex |
| Stellar Age | 7.500 Gyr |
| Apparent Magnitude | V: 13.225 · G: 12.973 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.752000 AU |
| Orbital Period | 872.2 days |
| Mean Orbital Velocity | 21.9 km/s |
| Orbital Eccentricity (e) | 0.49400 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.19 g/cm³ (110.6 km/s vesc) |
| Insolation Flux | 0.2084 S⊕ (~284 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 1134.500 LY (347.850 pc) |