HD 115404 A c
Astrophysical Synthesis & Habitability Characterization
HD 115404 A c is a confirmed gas giant exoplanet orbiting the star HD 115404 A, located approximately 35.8 light-years (10.98 parsecs) from the Solar System. First announced in 2022 by Multiple Observatories using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 12.5 Earth radii (1.12 Jupiter radii) and has a measured mass of 3279.671 Earth masses (10.32 Jupiter masses). Combining its mass and radius yields a mean bulk density of 9.26 g/cm³ (an iron-enriched, high-compression rocky core), a surface gravity of 20.99 g⊕ (205.84 m/s²), and an escape velocity of 181.2 km/s.
In its orbital architecture around HD 115404 A, HD 115404 A c completes one full revolution every 15319.225 Earth days (41.94Julian years) at a semi-major axis of 11.364 AU (a wide outer-system orbit beyond Jupiter's 5.20 AU distance in our Solar System). Its mean orbital velocity is approximately 8.1 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.211 carries the world between 8.9662 AU at periapsis and 13.7618 AU at apoapsis, driving measurable seasonal insolation cycles.
❄️ Thermal Regime (Cryogenic Zone): With an equilibrium temperature of 61 K (-212°C / -350°F) and an incident flux of 0.00 S⊕ (~3 W/m²), surface water and volatile species on HD 115404 A c would remain locked in cryogenic ice phases unless warmed by subsurface tidal or radiogenic heating.
The host star HD 115404 A is classified as an orange K-type star of spectral type K2V with an effective photospheric temperature of 5,019 K, a radius of 0.727 R☉, a mass of 0.83 M☉, an estimated bolometric luminosity of 0.301 L☉. Stellar evolution modeling indicates a metallicity of [Fe/H] = -0.157 dex (metal-poor relative to the Sun). From Earth, HD 115404 A shines at apparent V-band magnitude 6.501 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 115404 A system is a multi-planet architecture hosting 2 confirmed worlds, with HD 115404 A c sharing its stellar neighborhood alongside HD 115404 A 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 115404 A |
| Spectral Type | K2V |
| Effective Temp (Teff) | 5,019 K |
| Stellar Radius | 0.7270 R☉ |
| Stellar Mass | 0.8300 M☉ |
| Bolometric Luminosity | 0.301 L☉ |
| Metallicity [Fe/H] | -0.157 dex |
| Stellar Age | — |
| Apparent Magnitude | V: 6.501 · G: 6.286 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 11.364000 AU |
| Orbital Period | 15319.225 days |
| Mean Orbital Velocity | 8.1 km/s |
| Orbital Eccentricity (e) | 0.21100 |
| Orbital Inclination (i) | 25.7910° |
| Mean Bulk Density | 9.26 g/cm³ (181.2 km/s vesc) |
| Insolation Flux | 0.0023 S⊕ (~3 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 35.800 LY (10.982 pc) |