HD 145377 b
Astrophysical Synthesis & Habitability Characterization
HD 145377 b is a confirmed gas giant exoplanet orbiting the star HD 145377, located approximately 174.5 light-years (53.49 parsecs) from the Solar System. First announced in 2008 by La Silla Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.8 Earth radii (1.14 Jupiter radii) and has a measured mass of 1913.337 Earth masses (6.02 Jupiter masses). Combining its mass and radius yields a mean bulk density of 5.03 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 11.68 g⊕ (114.54 m/s²), and an escape velocity of 136.8 km/s.
In its orbital architecture around HD 145377, HD 145377 b completes one full revolution every 103.95 Earth days at a semi-major axis of 0.45 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 47.1 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.31, swinging from 0.3105 AU at periapsis out to 0.5895 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 443 K (+170°C / +338°F) and receiving 7.70 S⊕ (~10,485 W/m²), HD 145377 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 145377 is classified as a solar-type yellow star of spectral type G3 V with an effective photospheric temperature of 6,014 K, a radius of 1.05 R☉, a mass of 1.2 M☉, an estimated bolometric luminosity of 1.294 L☉. Stellar evolution modeling indicates an estimated stellar age of 1.3 Gyr and a metallicity of [Fe/H] = 0.11 dex (metal-rich relative to the Sun). From Earth, HD 145377 shines at apparent V-band magnitude 9.236 (accessible to binoculars and small amateur telescopes) in the Southern 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: La Silla Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 145377 |
| Spectral Type | G3 V |
| Effective Temp (Teff) | 6,014 K |
| Stellar Radius | 1.0500 R☉ |
| Stellar Mass | 1.2000 M☉ |
| Bolometric Luminosity | 1.294 L☉ |
| Metallicity [Fe/H] | 0.110 dex |
| Stellar Age | 1.300 Gyr |
| Apparent Magnitude | V: 9.236 · G: 7.970 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.450000 AU |
| Orbital Period | 103.95 days |
| Mean Orbital Velocity | 47.1 km/s |
| Orbital Eccentricity (e) | 0.31000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 5.03 g/cm³ (136.8 km/s vesc) |
| Insolation Flux | 7.7037 S⊕ (~10,485 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 174.500 LY (53.488 pc) |