Planetary Profile: Duskara

Name: HD Xanthea (colloquial: “Xanthea’s Star”)
Spectral Type: K3–K4 main-sequence star
Mass: ~0.8 Solar masses
Luminosity: ~0.3–0.4 Solar luminosities
Estimated Age: ~4–5 billion years
Habitable Zone: Relatively close-in orbits, suitable for tidally locked planets if atmospheric and geothermal conditions allow

Planet Name: Duskara
Orbital Distance: ~0.15 AU from HD Xanthea (varies slightly with eccentricity)
Orbital Period: ~30–35 Earth days (synchronous rotation leads to tidal locking)
Rotation: Tidally locked (one hemisphere faces the star constantly)
Axial Tilt: Minimal (≤ 1°), little to no seasonal variation

Diameter: ~1.00–1.05 × Earth’s diameter
Mass: ~1.00–1.10 × Earth’s mass
Surface Gravity: ~0.95–1.05 g (near Earth-normal)
Escape Velocity: Similar to Earth’s (slightly higher or lower depending on precise mass/radius)

Day Side:
- Surface Temperatures: ~350–450°C (subject to local conditions)
- Brutal solar flux, extreme UV and particle radiation
- Frequent dust storms in transition zone
- Minimal or no standing water at the surface
Night Side:
- Surface Temperatures: ~−100 to −150°C (variable by region)
- Permanently dark or in deep twilight from scattered auroras
- Glacial ice sheets, occasional geothermal vents or volcanic hotspots
- Some pockets of life in subterranean areas warmed by geothermal heat

Width: ~200–300 km band encircling the planet
Temperature Range: Generally −5°C to +40°C, depending on proximity to day or night side
Atmospheric Dynamics:
- Strong, persistent winds due to stark temperature gradient
- Frequent superstorms where hot and cold air masses meet
Habitable Zone: Nearly all surface settlements and farmland lie here; major cities form linear chains along temperate corridors

Composition (approx.):
- ~76–78% Nitrogen (N₂)
- ~20–22% Oxygen (O₂)
- ~1–3% Argon / other inert gases
- Trace amounts of CO₂, H₂O vapor, and exotic molecules
Surface Pressure: ~0.9–1.1 bar (near sea-level Earth equivalent)
Radiation & Weather:
- Enhanced stellar radiation on the day side; partial protection via thick atmosphere
- Robust wind circulation redistributing heat and moisture from day to twilight regions

Primary Water Reservoirs:
- Subterranean aquifers, glacial deposits on the night side
- Collection of atmospheric moisture in twilight and day-night transition storms
Surface Water:
- Present mainly in the form of rivers or small seas in the deeper parts of the twilight belt
- Lake- or river-like bodies fed by precipitation and geothermal springs
Geology:
- Tectonically active regions produce geothermal vents, crucial for night-side warmth
- Abundant mineral deposits in dayward highlands, mined by robotic systems

Native Flora & Fauna:
- Adapted to low light, high winds, or subterranean niches
- Some species show bioluminescence or specialized thermal regulation
- Deep-cave ecosystems rely heavily on geothermal/chemosynthetic processes
Human Settlements:
- Concentrated in twilight belt, forming linear “wind-hardened” cities
- Cave-dwelling communities near geothermal vents on night side
- Careful agriculture (vertical farming, hydroponics) in stable twilight microclimates