HD 195019 b
Astrophysical Synthesis & Habitability Characterization
HD 195019 b is a confirmed gas giant exoplanet orbiting the star HD 195019, located approximately 122.9 light-years (37.67 parsecs) from the Solar System. First announced in 1998 by Lick 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 1264.963 Earth masses (3.98 Jupiter masses). Combining its mass and radius yields a mean bulk density of 3.17 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 7.48 g⊕ (73.35 m/s²), and an escape velocity of 110.3 km/s.
In its orbital architecture around HD 195019, HD 195019 b completes one full revolution every 18.201 Earth days at a semi-major axis of 0.14 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 83.7 km/s (compared to Earth's 29.8 km/s). With a near-circular eccentricity of e = 0.01 (ranging from 0.1386 AU at periapsis to 0.1414 AU at apoapsis), the planet experiences minimal orbital distance variation.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 902 K (+629°C / +1164°F) and receiving 109.86 S⊕ (~149,522 W/m²), HD 195019 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 195019 is classified as a solar-type yellow star of spectral type G3 IV-V with an effective photospheric temperature of 5,751 K, a radius of 1.48 R☉, a mass of 1.21 M☉, an estimated bolometric luminosity of 2.15 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.2 Gyr and a metallicity of [Fe/H] = 0.05 dex (near-solar heavy-element abundance). From Earth, HD 195019 shines at apparent V-band magnitude 6.876 (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: Lick Observatory · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 195019 |
| Spectral Type | G3 IV-V |
| Effective Temp (Teff) | 5,751 K |
| Stellar Radius | 1.4800 R☉ |
| Stellar Mass | 1.2100 M☉ |
| Bolometric Luminosity | 2.15 L☉ |
| Metallicity [Fe/H] | 0.050 dex |
| Stellar Age | 3.200 Gyr |
| Apparent Magnitude | V: 6.876 · G: 6.729 |
| System Architecture | 2 Stars, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.140000 AU |
| Orbital Period | 18.201 days |
| Mean Orbital Velocity | 83.7 km/s |
| Orbital Eccentricity (e) | 0.01000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 3.17 g/cm³ (110.3 km/s vesc) |
| Insolation Flux | 109.8620 S⊕ (~149,522 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 122.900 LY (37.668 pc) |