Astronomy and Astrophysics II (Stellar Physics)

Semester I, Term II of the IUCAA-NCRA Graduate School 2019-2020

The final exam will be on 29th Nov 14:00-16:00 hrs in the NCRA Lecture Hall. The exam will be open notes exam.

Textbooks followed

Important Information

• This is a 14 lecture (1h each) course.
• The classes will start 2019, Oct 14. The classes will be on Monday, Wednesday and Friday of every week until the course duration at 10:00-11:00 hrs.
• There will be assessments during the course and a final exam. The assessments during the course include some take home assignments, and your general performance in the class.
• A credit of 40 per cent is reserved for assignments, 10 per cent for class performance, 25 per cent for the project and 25 per cent for the final exam.
• The final exam is on 29th Nov 14:00-16:00 hrs. This will be an open notes exam.
• You need to submit a 4 page report on the papers assigned to the group you are in. The last date for the report is also 29th November. An email has been sent with group name and the paper. Email me if you did not receive the email.
The papers for different groups are following

Paper for Team O
Paper for Team B
Paper for Team A
Paper for Team F (First three sections I, II, III)
Paper for Team G
Paper for Team K
Paper for Team M

Syllabus

• Lecture 1, 2019 Oct 14
  Introduction, Basic Properties of stars
  

  Assignment 1: (Submission date 21st Oct 2019)

  1:) Estimate the gravitational field due to Proxima Centauri on our Sun.
  2:) Show that magnetic field and rotation have negligible effect on Sun to deviate it's shape from spherical symmetry.
  3:) Why don't the different temperature curves intersect for blackbodies in Planck's diagram?
  
• Lecture 2, 2019 Oct 16
  Observational Classification of Stars, Harvard Classification, Yerkes Classification, Connecting with physical properties of stars
  

  Assignment 2: (Submission date 23rd Oct 2019)

  1:) Interpret the IR and UV spectra, in Lecture 2 slides, for different classes of stars.
  
• Lecture 3, 2019 Oct 18
  HR-Diagram, Stellar winds, Stellar Structure Equations
  

  Assignment 3: (Submission date 25th Oct 2019)

  1:) Download and play with the MESA code (Show the results by 15 Nov).
  2:) Estimate order of magnitude central pressure of a star of mass M. Assume surface pressure to be zero.
  
• Lecture 4, 2019 Oct 21
  Stellar Structure Equations, Virial Theorem, Total Energy of a star, Equations of energy transport, Energy transport mechanism
  

  Assignment 4: (Submission date 4th Nov 2019)

  1:) Estimate average temperature of a star of mass M and size R assuming it is a perfect gas system.
  2:) What happens to a star dominated by radiation pressure, in terms of total energy and stability?
  
• Lecture 5, 2019 Oct 23
  Opacity, Eddignton Luminosity, Adiabatic exponents
  

  Assignment 5: (Submission date 6th Nov 2019)

  1:) Obtain equation of motion under hydrostatic equilibrium in terms of optical depth.
  
• Lecture 6, 2019 Oct 23
  Convection, Nuclear Energy Generation
  

  Assignment 6: (Submission date 8th Nov 2019)

  1:) Luminosity of Sun is 4x1033 erg/s. How much H is burning every second?
  
• Lecture 7, 2019 Nov 04
  Nuclear Energy Generation, Gamow peak, Electron shielding, pp cycle, CNO cycle
  

  Assignment 7: (Submission date 11th Nov 2019)

  1:) If the temperature at the center of a star rises by 10 percent, how much more energy is generated by p-p chain? How much more energy is generated by CNO cycle?
  
• Lecture 8, 2019 Nov 06
  Nucleosynthesis, neutron capture, neutrinos
  

  Assignment 8: (Submission date 15th Nov 2019)

  1:) How many solar neutrinos passing through you per second?
  
• Lecture 9, 2019 Nov 08
  Simple stellar models, polytropic models, homology relations, dynamical and thermal stability of stars
  

  Assignment 8: (Submission date 15th Nov 2019)

  1:) Solve Lane-Emden equation for polytope of index n=0 and find M.
  
• Lecture 10, 2019 Nov 11
  Detailed numerical models of stellar evolution
  
• Lecture 11, 2019 Nov 15
  Evolution of intermediate mass stars and white dwarfs
  
• Lecture 12 & 13, 2019 Nov 19
  Massive star evolution, Stellar deaths, supernovae and GRBs, mass loss rates
  
• Lecture 14, 2019 Nov 20
  Compact stellar remnants, neutron stars, black holes