9 H. R. Diagram

V. B. Bhatia

The basic material is from Astronomy and Astrophysics with Elements of Cosmology by V. B. Bhatia. It has been amplified with the help of the following sources:

• http://abyss.uoregon.edu/~js/ast122/lectures/lec11.html
• http://www.atnf.csiro.au/outreach/education/senior/astrophysics/stellarevolution_hrintro.html
• https://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_diagram
• http://astro.unl.edu/naap/hr/hr_background3.html
• http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/herrus.html
• https://www.cliffsnotes.com/study-guides/astronomy/the-hertzsprung-russell-diagram/hertzsprung-russell-diagram-the-basicsweb.njit.edu/~gary/202/Lecture17.html
• http://chandra.harvard.edu/edu/formal/variable_stars/HR_student.html
• http://spiff.rit.edu/classes/phys230/lectures/hr/hr.html
• https://commons.wikimedia.org/wiki/File:M3_color_magnitude_diagram.jpg
• https://www.eso.org/public/images/eso0728c/

H. R. Diagram plays an important role in unravelling the story of stellar evolution. Many texts emphasize this aspect of H. R. Diagrams. Two excellent texts for this and other topics in astronomy are:

1. The Physical Universe: An Introduction to Astronomy by Frank H. Shu.

2. Astrophysical Concepts by Martin Harwit.