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Astronomy 535 Stellar Structure Evolution

Astronomy 535 Stellar Structure Evolution. Course Philosophy. “Crush them, crush them all!” -Professor John Feldmeier. Course Philosophy. Contextual stellar evolution What we see stars doing The stellar structure that makes stars look that way

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Astronomy 535 Stellar Structure Evolution

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  1. Astronomy 535Stellar Structure Evolution

  2. Course Philosophy “Crush them, crush them all!” -Professor John Feldmeier

  3. Course Philosophy Contextual stellar evolution • What we see stars doing • The stellar structure that makes stars look that way • The physical processes determining the stellar structure • How stars change with time • The impact of stars upon their environment

  4. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution My god,it’s full of stars

  5. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  6. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  7. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  8. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  9. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  10. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  11. Motivation for studying stellar evolution • Stars as ensembles • Clusters • Stellar populations • Starbursts • Stellar yields and environment • Luminosity: Interstellar radiation field, heating, photoionization • Kinetic Energy: Stellar winds, supernovae, feedback • Nucleosynthesis: Chemical evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution

  12. Motivation for studying stellar evolution • Evolution of ISM, IGM, gas fraction, composition, star formation, populations, galaxies, baryonic matter in general profoundly depends on stellar evolution • Fits of models to observations by means of free parameters is standard procedure, but gives unreliable or downright bad results for most applications • Must be able to predict evolution of a star as a function of mass and composition to high accuracy • Also necessary to understand individual objects

  13. Quantitative Uncertainties in Yields for Massive Stars • Luminosity: • factors of 2 by 25 M • Larger radii, lower Teff, fewer ionizing photons • IMFs derived from observed luminosity functions • Kinetic energy • Order of magnitude uncertainties in mass loss rates • complete uncertainty in composition of winds for a given star • Nucleosynthetic • 2 orders of magnitude in Fe peak abundances from progenitors, reaction calculations, supernova explosion calculations, etc.

  14. How to study stars • Too many stellar models are black boxes - tuning a free parameter (i.e. overshooting) to fit one particular observation allows you to predict nothing about other stars

  15. How to study stars • Too many stellar models are black boxes - tuning a free parameter (i.e. overshooting) to fit one particular observation allows you to predict nothing about other stars • Stars are not black boxes - including complete physics in a stellar model should give you a correct model

  16. How to study stars • Too many stellar models are black boxes - tuning a free parameter (i.e. overshooting) to fit one particular observation allows you to predict nothing about other stars • Stars are not black boxes - including complete physics in a stellar model should give you a correct model • Stars are plasma physics problems - must account for B fields, ionization, multi-component EOS, & charge effects on reactions, radiation transport, hydrostatics, & dynamics

  17. How to study stars • 3-pronged approach • Theory based on analytical work and simulations • Terrestrial High Energy Density experiments with lasers and other facilities approximate stellar conditions • Observational tests of theoretical models identify deficiencies in physics, not fits to free parameters

  18. How to study stars • 3-pronged approach • Theory based on analytical work and simulations • Terrestrial High Energy Density experiments with lasers and other facilities approximate stellar conditions • Observational tests of theoretical models identify deficiencies in physics, not fits to free parameters

  19. How to study stars • 3-pronged approach • Theory based on analytical work and simulations • Terrestrial High Energy Density experiments with lasers and other facilities approximate stellar conditions • Observational tests of theoretical models identify deficiencies in physics, not fits to free parameters

  20. Syllabus 1/11 Intro to class Motivation for studying stars Syllabus Timescales 1/13 Equations of hydrodynamics Sound waves Hydrostatic equilibrium Mass-Luminosity relations 1/16 MLK Holiday 1/18 Convection Waves 1/20 Waves Rotation 1/23 **Patrick Leaves for Santa Barbara** EOS Opacities Abundances

  21. Syllabus 1/25 Nuclear reactions TYCHO 1/27 The HR diagram CMDs High mass vs. low mass Introduce project 1 (MS as f(z)) 1/30 Pre-MS 2/1 Low mass objects Main sequence starts HW: burning timescales 2/3 pp vs. CNO Convection pp vs. CNO all the problems thereof 2/6 Probably more convection Rotation

  22. Syllabus 2/8 Mass-Luminosity relation & lifetimes Cluster ages Composition effects Fun opacity sources 2/10 Misc & catch-up 2/13 **Patrick returns from Santa Barbara** Presentations 2/15 Presentations 2/17 Presentations 2/20 Mass loss Very massive stars Pop III

  23. Syllabus 2/22 Post-MS H exhaustion Shell burning RGB 2/24 3alpha degeneracy Tip of RGB He flash 2/27 Red clump/BHB Stellar pulsations Cepheids kappa mechanism

  24. Syllabus 3/1 Double shell burning AGB Ratio of BHB/AGB 3/3 C stars, extreme pop II Thermal pulse s-process 3/6 Mass loss PN ejection White dwarfs 3/8 Massive stars Mass loss Wolf Rayets Kinetic luminosity & feedback 3/10 3/13 - 3/17 Spring Break

  25. Syllabus 3/20 Presentations 3/22 Presentations 3/24 Presentations 3/27 Misc. & catch-up 3/29 C ignition neutrino cooling C burning 3/31 Ne burning O burning weak interactions

  26. Syllabus 4/3 Dynamics of the shell URCA Flame fronts & wierd burning 4/5 detailed balance & thermodynamic consistency QSE NSE Si burning 4/7 Core collapse Nuclear reactions 4/10 Neutrinos Mechanisms 4/12 Asymmetries Mixing Explosive nucleosynthesis 4/14 alpha-rich freezeout r-process uncertainties in nucleo

  27. Syllabus 4/17 Core collapse types Spectra Lightcurves 87A 4/19 Type 1a Pair instability GRBs 4/21 GRBs compact objects CVs & XRBs 4/24 **Patrick leaves for Nepal** Population synthesis Stellar pops (Christy?)

  28. Syllabus 4/26 Misc. & catch-up 4/28 Presentations 5/1 Presentations 5/3 Presentations

  29. Timescales Gravitational timescale Hydrodynamic timescale Note that in hydrostatic equilibrium Hydrostatic adjustment timescale at 1M White Dwarf: few s Main sequence: 27 min (sun) Red Giant: 18 days For most phases HSE << evol

  30. Timescales Kelvin-Helmholtz (Thermal) For sun KH ~ 10 Myr

  31. Timescales Nuclear or Evolutionary Timescale Quick ‘n’ dirty solar lifetime estimate QHHe=6.3x1018erg g-1(0.7% of rest mass energy) assume 10% of H gets burned Enuc = 2x1033g x 0.1 x 0.007 x c2 = 1.26x1051 erg L = 4x1033 erg  3x1017 s = 10 Gyr

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