HD 143105 b
Astrophysical Synthesis & Habitability Characterization
HD 143105 b is a confirmed gas giant exoplanet orbiting the star HD 143105, located approximately 152.6 light-years (46.78 parsecs) from the Solar System. First announced in 2016 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.7 Earth radii (1.22 Jupiter radii) and has a measured mass of 384.574 Earth masses (1.21 Jupiter masses). Combining its mass and radius yields a mean bulk density of 0.82 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 2.05 g⊕ (20.1 m/s²), and an escape velocity of 59.3 km/s.
In its orbital architecture around HD 143105, HD 143105 b completes one full revolution every 2.197 Earth days at a semi-major axis of 0.0379 AU (an ultra-close orbit less than one-seventh of Mercury's 0.387 AU distance from the Sun, where strong stellar tidal forces typically induce synchronous rotation). Its mean orbital velocity is approximately 187.6 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.07 carries the world between 0.0352 AU at periapsis and 0.0406 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 2028 K (+1755°C / +3191°F) and receiving 2,502.00 S⊕ (~3,405,225 W/m²), HD 143105 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 143105 is classified as a warm F-type star of spectral type F5 with an effective photospheric temperature of 6,380 K, a radius of 1.6473 R☉, a mass of 1.51 M☉, an estimated bolometric luminosity of 4.034 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = 0.15 dex (metal-rich relative to the Sun). From Earth, HD 143105 shines at apparent V-band magnitude 6.77 (accessible to binoculars and small amateur telescopes) in the Northern 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: Haute-Provence Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 143105 |
| Spectral Type | F5 |
| Effective Temp (Teff) | 6,380 K |
| Stellar Radius | 1.6473 R☉ |
| Stellar Mass | 1.5100 M☉ |
| Bolometric Luminosity | 4.034 L☉ |
| Metallicity [Fe/H] | 0.150 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 6.770 · G: 6.626 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.037900 AU |
| Orbital Period | 2.197 days |
| Mean Orbital Velocity | 187.6 km/s |
| Orbital Eccentricity (e) | 0.07000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 0.82 g/cm³ (59.3 km/s vesc) |
| Insolation Flux | 2502.0025 S⊕ (~3,405,225 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 152.600 LY (46.779 pc) |