HD 88986 b
Astrophysical Synthesis & Habitability Characterization
HD 88986 b is a confirmed sub-neptune exoplanet orbiting the star HD 88986, located approximately 108.5 light-years (33.27 parsecs) from the Solar System. First announced in 2023 by Haute-Provence Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.49 Earth radii and has a measured mass of 17.2 Earth masses. Combining its mass and radius yields a mean bulk density of 6.14 g/cm³ (a terrestrial silicate-iron composition comparable to Earth (5.51 g/cm³)), a surface gravity of 2.77 g⊕ (27.16 m/s²), and an escape velocity of 29.4 km/s.
In its orbital architecture around HD 88986, HD 88986 b completes one full revolution every 146.05 Earth days at a semi-major axis of 0.58 AU (situated at an orbital separation between Mercury's 0.39 AU and Venus's 0.72 AU). Its mean orbital velocity is approximately 43.2 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.24 carries the world between 0.4408 AU at periapsis and 0.7192 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 460 K (+187°C / +369°F) and receiving 7.35 S⊕ (~10,009 W/m²), HD 88986 b orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 88986 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,861 K, a radius of 1.543 R☉, a mass of 1.25 M☉, an estimated bolometric luminosity of 2.521 L☉. Stellar evolution modeling indicates an estimated stellar age of 7.9 Gyr and a metallicity of [Fe/H] = 0.06 dex (metal-rich relative to the Sun). From Earth, HD 88986 shines at apparent V-band magnitude 6.47 (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 88986 |
| Spectral Type | G2 V |
| Effective Temp (Teff) | 5,861 K |
| Stellar Radius | 1.5430 R☉ |
| Stellar Mass | 1.2500 M☉ |
| Bolometric Luminosity | 2.521 L☉ |
| Metallicity [Fe/H] | 0.060 dex |
| Stellar Age | 7.900 Gyr |
| Apparent Magnitude | V: 6.470 · G: 6.303 |
| System Architecture | 1 Star, 1 Planet |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.580000 AU |
| Orbital Period | 146.05 days |
| Mean Orbital Velocity | 43.2 km/s |
| Orbital Eccentricity (e) | 0.24000 |
| Orbital Inclination (i) | 89.9000° |
| Mean Bulk Density | 6.14 g/cm³ (29.4 km/s vesc) |
| Insolation Flux | 7.3543 S⊕ (~10,009 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 108.500 LY (33.267 pc) |