HD 35843 b
Astrophysical Synthesis & Habitability Characterization
HD 35843 b 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 Paranal Observatory using the Radial Velocity detection technique (measuring periodic Doppler reflex motion in the host star's spectrum), this world measures 2.29 Earth radii and has a measured mass of 5.84 Earth masses. Combining its mass and radius yields a mean bulk density of 2.68 g/cm³ (an intermediate density indicative of a deep water-ice mantle or dense volatile envelope), a surface gravity of 1.11 g⊕ (10.89 m/s²), and an escape velocity of 17.9 km/s.
In its orbital architecture around HD 35843, HD 35843 b completes one full revolution every 9.899 Earth days at a semi-major axis of 0.088 AU (orbiting interior to Mercury's 0.387 AU benchmark in the Solar System). Its mean orbital velocity is approximately 96.7 km/s (compared to Earth's 29.8 km/s). The orbit is modeled as circular (e = 0.00), maintaining a constant stellar distance throughout its year.
⚠️ Thermal Regime (Irradiated / Hot Zone): At an equilibrium temperature of 872 K (+599°C / +1110°F) and receiving 96.85 S⊕ (~131,812 W/m²), HD 35843 b 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 b sharing its stellar neighborhood alongside HD 35843 c.
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: Paranal Observatory · 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) | 0.088000 AU |
| Orbital Period | 9.899 days |
| Mean Orbital Velocity | 96.7 km/s |
| Orbital Eccentricity (e) | 0.00000 |
| Orbital Inclination (i) | — |
| Mean Bulk Density | 2.68 g/cm³ (17.9 km/s vesc) |
| Insolation Flux | 96.8492 S⊕ (~131,812 W/m²) |
| Habitable Zone Status | Exterior / Non-HZ |
| Celestial Distance | 227.000 LY (69.603 pc) |