HD 25723 b
Astrophysical Synthesis & Habitability Characterization
HD 25723 b is a confirmed gas giant exoplanet orbiting the star HD 25723, located approximately 374.5 light-years (114.82 parsecs) from the Solar System. First announced in 2020 by Lick Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 13.3 Earth radii (1.19 Jupiter radii) and has a measured mass of 794.571 Earth masses (2.5 Jupiter masses). Combining its mass and radius yields a mean bulk density of 1.86 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 4.49 g⊕ (44.03 m/s²), and an escape velocity of 86.5 km/s.
In its orbital architecture around HD 25723, HD 25723 b completes one full revolution every 457.01 Earth days (1.25Julian years) at a semi-major axis of 1.49 AU (comparable to the inner terrestrial zone between Venus, Earth at 1.00 AU, and Mars at 1.52 AU). Its mean orbital velocity is approximately 35.5 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.04 (ranging from 1.4304 AU at periapsis to 1.5496 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 698 K (+425°C / +797°F) and receiving 39.63 S⊕ (~53,941 W/m²), HD 25723 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 25723 is classified as an orange K-type star of spectral type K1 III with an effective photospheric temperature of 4,766 K, a radius of 13.76 R☉, a mass of 2.12 M☉, an estimated bolometric luminosity of 87.648 L☉. Stellar evolution modeling indicates an estimated stellar age of 0.95 Gyr and a metallicity of [Fe/H] = -0.03 dex (near-solar heavy-element abundance). From Earth, HD 25723 shines at apparent V-band magnitude 5.601 (visible to the unaided human eye under dark skies) 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: Lick Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 25723 |
| Spectral Type | K1 III |
| Effective Temp (Teff) | 4,766 K |
| Stellar Radius | 13.7600 R☉ |
| Stellar Mass | 2.1200 M☉ |
| Bolometric Luminosity | 87.648 L☉ |
| Metallicity [Fe/H] | -0.030 dex |
| Stellar Age | 0.950 Gyr |
| Apparent Magnitude | V: 5.601 · G: 5.319 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 1.490000 AU |
| Orbital Period | 457.01 days |
| Mean Orbital Velocity | 35.5 km/s |
| Orbital Eccentricity (e) | 0.04000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 1.86 g/cm³ (86.5 km/s vesc) |
| Insolation Flux | 39.6333 S⊕ (~53,941 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 374.500 LY (114.816 pc) |