Credible intervals for the sound speed and proton fraction in neutron-star matter. (IMAGE)
Caption
The figure presents two quantities directly linked to the composition and stiffness of matter inside neutron stars. Higher-precision radius data generally favor lower sound speeds and tighter pressure-related constraints, but the proton fraction behaves differently across functionals because it is strongly tied to the symmetry energy. The horizontal reference lines mark thresholds relevant to direct Urca cooling and the conformal limit.
Credit
Wen-Jie Xie
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Credit must be given to the creator. Only noncommercial uses of the work are permitted.
License
CC BY-NC