1. Model Spectra of Neutron Star Surface Thermal Emission Department of Physics National Tsing Hua University Lun-Wen Yeh 2003.10.2

2. Assumption Plane-parallel atmosphere Radiation equilibrium Ideal gas Z=1 Neglect conduction and convection No magnetic field The physical properties independent of time

3. Structure of neutron star Radiation transfer equation Temperature correction Flux ≠const Flux = const Spectrum P(τ) ρ(τ) T(τ)

4. Structure of neutron star Gray atmosphere: Equation of state: ideal gas (ionize H) Oppenheimer-Volkoff: Thomson depth

5. Radiation transfer equation Absorption Spontaneous emissionInduced emission Scattering

6. Interior of star atmosphere Boundary condition Feautrier method

7. Boundary condition Define Boundary condition

8. atmosphereInterior of star Boundary condition

9. Substitute into boundary condition

10. We have flux!! ^^ Then using temperature-correction and resolving radiation equation until flux approach constant and expected numerical values.

11. Further work test Feautrier method Read more detail about this method and some physical formula deriving some physical formula deriving Add directions, frequencies Temperature-correction Add magnetic field Ex: Eddington factor,… Ex :opacity,….