lec29 - Lecture 29 Neutron Stars and Black Holes Lecture 29...

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Lecture 29 Neutron Stars and Black Holes Purdue University, Astronomy 364 1 Lecture 29
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Neutron stars • If a degenerate core (or white dwarf) exceeds the Chandrasekhar mass limit (1.4M Sun ) it must collapse until neutron degeneracy pressure takes over. M 1.4 M Sun R 10 km ρ≈ 6.65 × 10 17 kg / m 3 2.9 ρ nuclear
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Degenerate Neutrons Heisenberg uncertainty principle: Δ x Δ p 2 For an electron confined to a volume V ~ n n -1 , we have x~V 1/3 ~ n n -1/3 . Therefore, the minimum momentum of the electron is p n ~ Δ p ~ Δ x ~ n n 1/3 . The pressure arisen from this (non-relativistic) motion is P degen ~ n n m n v n 2 n n m n p n m n 2   2 n n 5/3 m n . Lecture 29 3 Purdue University, Astronomy 364
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Lecture 29 Purdue University, Astronomy 364 4 For neutron stars, the support is provided by the neutron degeneracy pressure P c = P degen G M 2 R 4   2 n n 5/3 m n R 11 km M 1.4 M 1/3 . The escape velocity from a neutron star is
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This note was uploaded on 04/23/2011 for the course ASTR 364 taught by Professor Cui,weik. during the Spring '11 term at Purdue University-West Lafayette.

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lec29 - Lecture 29 Neutron Stars and Black Holes Lecture 29...

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