Review H-R diagrams and stellar life cycles in Edexcel A-Level Physics through star-cluster ageing, fusion stages and evolutionary paths.
The astronomer Hertzsprung used parallax to determine the distances to some of the variable stars known as Cepheids.
The Sun is a yellow star with a surface temperature of about 6000 K . In the 20th century, astronomers discovered a large variety of stars in our galaxy. Hertzsprung and Russell developed the Hertzsprung-Russell (HR) diagram as a way of classifying stars.
An HR diagram is shown below.
*(iii) The position of a star on the HR diagram changes as the star evolves. Explain how a star like the Sun evolves as it progresses from zone Z3 to its final position on the HR diagram.
