HD 68988 c
Astrophysical Synthesis & Habitability Characterization
HD 68988 c is a confirmed gas giant exoplanet orbiting the star HD 68988, located approximately 198.4 light-years (60.85 parsecs) from the Solar System. First announced in 2021 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.2 Earth radii (1.09 Jupiter radii) and has a measured mass of 4776.961 Earth masses (15.03 Jupiter masses). Combining its mass and radius yields a mean bulk density of 14.51 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 32.09 g⊕ (314.7 m/s²), and an escape velocity of 221.3 km/s.
In its orbital architecture around HD 68988, HD 68988 c completes one full revolution every 16000 Earth days (43.81Julian years) at a semi-major axis of 13.2 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 9 km/s (compared to Earth's 29.8 km/s). The planet follows a highly eccentric trajectory (e = 0.45, swinging from 7.26 AU at periapsis out to 19.14 AU at apoapsis), pointing to past dynamical scattering or secular gravitational perturbations.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 88 K (-185°C / -301°F) and an incident flux of 0.01 S⊕ (~13 W/m²), surface water and volatile species on HD 68988 c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 68988 is classified as a solar-type yellow star of spectral type G2 V with an effective photospheric temperature of 5,883 K, a radius of 1.2557 R☉, a mass of 1.1717 M☉, an estimated bolometric luminosity of 1.695 L☉. Stellar evolution modeling indicates an estimated stellar age of 6 Gyr and a metallicity of [Fe/H] = 0.305 dex (metal-rich relative to the Sun). From Earth, HD 68988 shines at apparent V-band magnitude 8.2 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 68988 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 68988 c sharing its stellar neighborhood alongside HD 68988 b.
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: Multiple Observatories · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 68988 |
| Spectral Type | G2 V |
| Effective Temp (Teff) | 5,883 K |
| Stellar Radius | 1.2557 R☉ |
| Stellar Mass | 1.1717 M☉ |
| Bolometric Luminosity | 1.695 L☉ |
| Metallicity [Fe/H] | 0.305 dex |
| Stellar Age | 6.000 Gyr |
| Apparent Magnitude | V: 8.200 · G: 8.046 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 13.200000 AU |
| Orbital Period | 16000 days |
| Mean Orbital Velocity | 9 km/s |
| Orbital Eccentricity (e) | 0.45000 |
| Orbital Inclination (i) | 93.0000° |
| Mean Bulk Density | 14.51 g/cm³ (221.3 km/s vesc) |
| Insolation Flux | 0.0096 S⊕ (~13 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 198.400 LY (60.845 pc) |