ASTROPHY-EOS v2.6

Mega-Earth GJ 523b Planetary Composition Studio

Planetary Presets M-R Benchmark
Physical Properties Direct Input
Planetary Mass ($M_p$) 23.00 M_⊕
Planetary Radius ($R_p$) 2.50 R_⊕
Core Radius Fraction (CRF) 0.33
Volatile / H-He Envelope Fraction 1.0 %
Computed Bulk Physics Derived
Bulk Density ($\rho$) 8.11 g/cm³ (1.47 $\rho_\oplus$)
Surface Gravity ($g$) 3.68 g_⊕ (36.09 m/s²)
Escape Velocity ($v_{\text{esc}}$) 33.9 km/s (3.03 $v_{\oplus}$)
Core-Mantle Pressure 1,420 GPa (Ultra-high P)
Mass–Radius Equation of State (EOS) Zapolsky-Salpeter / Seager et al.
100% Fe Core
Earth-like (32.5% Fe/Silicate)
100% Water / Ice VII
+2% H/He Envelope
Selected Target
Interior Cross-Section Cutaway Radial Shell Model
Solid/Liquid Fe Core: 33%
High-P Silicate Mantle: 66%
Residual H/He Atmo: 1%
Transit Chord Depth: 2.50 R_⊕

Atmospheric Stripping & Photoevaporation History

With a massive gravitational well ($v_{\text{esc}} = 33.9\text{ km/s}$) and high bulk density ($8.11\text{ g/cm}^3$), GJ 523b resides in the rare "Mega-Earth" desert. Hydrodynamic XUV photoevaporation and core-powered mass loss stripped its primordial gas envelope, leaving an ultra-compressed rocky core.

Stripped Primordial Envelope

Astrophysical Significance & Counterfactual Test

If GJ 523b had retained even a 5% H/He envelope by mass, degenerate gas physics would expand its observed radius to ~3.8 R_⊕, categorizing it as a temperate Sub-Neptune rather than a bare terrestrial Mega-Earth.

Empirical Benchmark: Kepler-10c / TOI-849b comparison set.
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