The red giant problem
Stories from Physics for 11-14 14-16
Astrophysicists struggled to understand how red giant stars could be very much more luminous than main sequence stars that were at similar effective temperatures – the so-called ‘red giant problem’. The problem arose early in the 1900s partly because Sir Arthur Eddington’s influential stellar models had assumed that stars were homogeneous. At the end of the 1930s, Ernst Öpik (see page 36) suggested that nuclear fusion might occur only in a shell beyond the core of the red giant, leading to the resolution of the problem and the development of better models of the giant stars.