HD 152843 c
Astrophysical Synthesis & Habitability Characterization
HD 152843 c is a confirmed sub-neptune exoplanet orbiting the star HD 152843, located approximately 351.9 light-years (107.9 parsecs) from the Solar System. First announced in 2021 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.145% across the stellar disk), this world measures 5.94 Earth radii (0.53 Jupiter radii) and has a measured mass of 9.67 Earth masses. Combining its mass and radius yields a mean bulk density of 0.25 g/cm³ (a low bulk density dominated by an extended hydrogen-helium gaseous envelope), a surface gravity of 0.27 g⊕ (2.65 m/s²), and an escape velocity of 14.3 km/s.
In its orbital architecture around HD 152843, HD 152843 c completes one full revolution every 19.502 Earth days at a semi-major axis of 0.1482 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 82.7 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.074 carries the world between 0.1372 AU at periapsis and 0.1592 AU at apoapsis, driving measurable seasonal insolation cycles.
☁️ Atmospheric Regime (Volatile / Gas Envelope): With a radius of 5.940 R⊕, HD 152843 c exceeds the empirical ~1.8–2.2 R⊕ Fulton radius valley threshold, indicating a substantial hydrogen-helium or supercritical volatile envelope without a conventional solid terrestrial surface.
The host star HD 152843 is classified as a solar-type yellow star of spectral type G0 with an effective photospheric temperature of 6,310 K, a radius of 1.43 R☉, a mass of 1.15 M☉, an estimated bolometric luminosity of 2.909 L☉. Stellar evolution modeling indicates an estimated stellar age of 3.97 Gyr and a metallicity of [Fe/H] = -0.16 dex (metal-poor relative to the Sun). From Earth, HD 152843 shines at apparent V-band magnitude 8.855 (accessible to binoculars and small amateur telescopes) in the Northern celestial hemisphere. The HD 152843 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 152843 c sharing its stellar neighborhood alongside HD 152843 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: Transiting Exoplanet Survey Satellite (TESS) · Catalogue Source: NASA Exoplanet Archive (IPAC / Caltech).
☀️ Host Star Telemetry
| Host Star Name | HD 152843 |
| Spectral Type | G0 |
| Effective Temp (Teff) | 6,310 K |
| Stellar Radius | 1.4300 R☉ |
| Stellar Mass | 1.1500 M☉ |
| Bolometric Luminosity | 2.909 L☉ |
| Metallicity [Fe/H] | -0.160 dex |
| Stellar Age | 3.970 Gyr |
| Apparent Magnitude | V: 8.855 · G: 8.764 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.148200 AU |
| Orbital Period | 19.502 days |
| Mean Orbital Velocity | 82.7 km/s |
| Orbital Eccentricity (e) | 0.07400 |
| Orbital Inclination (i) | 89.2100° |
| Mean Bulk Density | 0.25 g/cm³ (14.3 km/s vesc) |
| Insolation Flux | 133.1000 S⊕ (~181,149 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 351.900 LY (107.898 pc) |