HD 184010 d
Astrophysical Synthesis & Habitability Characterization
HD 184010 d is a confirmed gas giant exoplanet orbiting the star HD 184010, located approximately 198.3 light-years (60.8 parsecs) from the Solar System. First announced in 2022 by Okayama Astrophysical Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 14.3 Earth radii (1.28 Jupiter radii) and has a measured mass of 143.023 Earth masses (0.45 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.27 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.7 g⊕ (6.86 m/s²), and an escape velocity of 35.4 km/s.
In its orbital architecture around HD 184010, HD 184010 d completes one full revolution every 836.4 Earth days (2.29Julian years) at a semi-major axis of 1.92 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 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 381 K (+108°C / +226°F) and receiving 3.55 S⊕ (~4,833 W/m²), HD 184010 d orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 184010 is classified as an orange K-type star of spectral type K0 III-IV with an effective photospheric temperature of 4,971 K, a radius of 4.86 R☉, a mass of 1.35 M☉, an estimated bolometric luminosity of 12.94 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.76 Gyr and a metallicity of [Fe/H] = -0.17 dex (metal-poor relative to the Sun). From Earth, HD 184010 shines at apparent V-band magnitude 5.886 (visible to the unaided human eye under dark skies) in the Northern celestial hemisphere. The HD 184010 system is a multi-planet architecture hosting 3 confirmed worlds, with HD 184010 d sharing its stellar neighborhood alongside HD 184010 b, HD 184010 c.
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: Okayama Astrophysical Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 184010 |
| Spectral Type | K0 III-IV |
| Effective Temp (Teff) | 4,971 K |
| Stellar Radius | 4.8600 R☉ |
| Stellar Mass | 1.3500 M☉ |
| Bolometric Luminosity | 12.94 L☉ |
| Metallicity [Fe/H] | -0.170 dex |
| Stellar Age | 2.760 Gyr |
| Apparent Magnitude | V: 5.886 · G: 5.645 |
| System Architecture | 1 Star, 3 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.920000 AU |
| Orbital Period | 836.4 days |
| Mean Orbital Velocity | 25 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.27 g/cm³ (35.4 km/s vesc) |
| Insolation Flux | 3.5509 S⊕ (~4,833 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 198.300 LY (60.799 pc) |