HD 35843 c
Astrophysical Synthesis & Habitability Characterization
HD 35843 c is a confirmed sub-neptune exoplanet orbiting the star HD 35843, located approximately 227 light-years (69.6 parsecs) from the Solar System. First announced in 2025 by Transiting Exoplanet Survey Satellite (TESS) using the Transit detection technique (producing an estimated primary transit depth of 0.0674% across the stellar disk), this world measures 2.54 Earth radii and has a measured mass of 11.32 Earth masses. Combining its mass and radius yields a mean bulk density of 3.81 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.75 g⊕ (17.16 m/s²), and an escape velocity of 23.6 km/s.
In its orbital architecture around HD 35843, HD 35843 c completes one full revolution every 46.962 Earth days at a semi-major axis of 0.25 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 57.9 km/s (compared to Earth's 29.8 km/s). Its moderate orbital eccentricity of e = 0.153 carries the world between 0.2118 AU at periapsis and 0.2883 AU at apoapsis, driving measurable seasonal insolation cycles.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 479 K (+206°C / +403°F) and receiving 11.38 S⊕ (~15,490 W/m²), HD 35843 c orbits interior to the runaway greenhouse boundary where surface liquid water cannot persist.
The host star HD 35843 is classified as a stellar host with an effective photospheric temperature of 5,666 K, a radius of 0.897 R☉, a mass of 0.94 M☉, an estimated bolometric luminosity of 0.744 L☉. Stellar evolution modeling indicates an estimated stellar age of 2.5 Gyr and a metallicity of [Fe/H] = -0.27 dex (metal-poor relative to the Sun). From Earth, HD 35843 shines at apparent V-band magnitude 9.36 (accessible to binoculars and small amateur telescopes) in the Southern celestial hemisphere. The HD 35843 system is a multi-planet architecture hosting 2 confirmed worlds, with HD 35843 c sharing its stellar neighborhood alongside HD 35843 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 35843 |
| Spectral Type | Unclassified |
| Effective Temp (Teff) | 5,666 K |
| Stellar Radius | 0.8970 R☉ |
| Stellar Mass | 0.9400 M☉ |
| Bolometric Luminosity | 0.744 L☉ |
| Metallicity [Fe/H] | -0.270 dex |
| Stellar Age | 2.500 Gyr |
| Apparent Magnitude | V: 9.360 · G: 9.196 |
| System Architecture | 1 Star, 2 Planets |
🪐 Orbital & Physical Dynamics
| Semi-Major Axis (a) | 0.250000 AU |
| Orbital Period | 46.962 days |
| Mean Orbital Velocity | 57.9 km/s |
| Orbital Eccentricity (e) | 0.15300 |
| Orbital Inclination (i) | 89.5800° |
| Mean Bulk Density | 3.81 g/cm³ (23.6 km/s vesc) |
| Insolation Flux | 11.3814 S⊕ (~15,490 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 227.000 LY (69.603 pc) |