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Decoding Stellar Structure: A Journey Through Masses and Magic Numbers

Explore stellar evolution, from initial masses to magic numbers, unlocking the mysteries of stars through chance, probability, and physics. Understand the meaning and interpretation in astronomy, experiencing the essence of stellar structure and evolution.

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Decoding Stellar Structure: A Journey Through Masses and Magic Numbers

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  1. Characteristic initial masses Chang, Seo-Won

  2. Magic Numbers? • 6563, 4861, 3968, 3933, …. • 1100, 3000, 0, 2.73 • 4, 19, 26, 27, 30, 42 • 0.08, 1.1, 1.8-2.2, 8 , 60 (1) Lotto = Chance & Probability (2) Physics = Meaning & interpretation (3) Astronomy = Experience & Feeling & (1) & (2) & ….

  3. Stellar structure & Evolution • T • P • M • E

  4. MH ~ 0.08 M⊙ on MS • ‘H’ means Hydrogen • Less massive than MH : never burn H • Brown dwarf & Black dwarf

  5. Mconv ~ 1.1 M⊙ on MS • ‘conv’ means Convection • More massive than Mconv : Have Convective cores (engulfs the core only ~ @1.5 M⊙) • Why they have convective cores?

  6. MHeF ~ 1.8-2.2 M⊙ on MS • ‘HeF’ means Helium Flash • Depending on the X, Y, Z • Less massive than MHeF : experience HeF (explosive ignition of He core ~ 0.45 M⊙) • More massive than MHeF : Fig 5-5.

  7. Mup ~ 8 M⊙ on MS • ‘up’ means … • C ignite quiescently in the core (~50 M⊙ -> Fe-peak nuclei) • Core implodes leads to the formation of either a neutron star or a black hole (Fig 5.6).

  8. Mee ~ 60 M⊙ on MS • ‘ee’ means e-e+ (pair-production instability) • Unstable before forming Fe core (largely O core @ instability) • Te ~ 2 x 107 K • Several Pulsations

  9. Mi ~ Mr • Remnant-mass-initial-mass relation (Fig 5.7). • Stellar Evolution • Mi > 0.8 M⊙ : climbs slowly (WD) • Mi = 8 M⊙ : Transition (WD -> NS), Mr = 1.4 • Mi = 60-90M⊙ : Uncertain (NS -> BH), 1.4 < Mr < 3M⊙ Mr Mi

  10. In particular.. • It makes clear that stars eventually return most of their mass to the ISM.

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