Stars as Laboratories for Fundamental Physics - MPP Theory Group

Characteristics of Stellar Plasmas 599
Table D.1. Plasma characteristics for some typical astrophysical sites.
Center of Red-giant core
standard Core of just before
solar model HB stars helium ignition White dwarf
Characteristic nondegenerate nondegenerate degenerate degenerate
nonrelativistic nonrelativistic weakly coupled strongly coupled
Temperature 1.55×10 7 K ≈ 10 8 K ≈ 10 8 K 3×10 6 −2×10 7 K
= 1.3 keV = 8.6 keV = 8.6 keV = 0.3−1.7 keV
Density 156 g cm −3 ≈ 10 4 g cm −3 ≈ 10 6 g cm −3 1.8×10 6 g cm −3 ( a )
Composition X = 0.35 4
He,
12 C,
16 O
4 He
12 C,
16 O
Electron density 6.3×10 25 cm −3 3.0×10 27 cm −3 3.0×10 29 cm −3 5.3×10 29 cm −3
Fermi momentum 24.3 keV 88 keV 409 keV 495 keV
Fermi energy b 0.58 keV 7.6 keV 144 keV 200 keV
Plasma frequency 0.3 keV 2.0 keV 18 keV 23 keV
Plasma coupling Γ = 0.07 0.12 0.57 144−22
Debye screening electrons + ions electrons + ions ions —
kS = (k D 2 + k i 2 ) 1/2 kS = (k D 2 + k i 2 ) 1/2 kS = ki (strong
= 9.1 keV = 27 keV = 222 keV screening)
a Center of WD with M = 0.66 M ⊙.
b Nonrelativstic Fermi energy E F − me.