This is called the 'red giant' phase of a star's evolution (see below). As a result, these outer layers expand to dissipate the heat being generated, becoming large and highly luminous. A main sequence star chart, or Hertzsprung-Russell (HR) diagram, is a chart which shows the relationship between a star's luminosity and their stellar classification, or effective temperature. Without the heat generated by fusion, the core begins a gravitational collapse, which consequently creates more heat and pressure, triggering fusion in the outer layers of the star where hydrogen fuel still remains. This first occurs in the stellar core as this is the hottest and heaviest region. 2) B type stars: They are also massive but non-supergiant blue stars. They are 15-90 times massive than the sun. 1) O type stars: The most massive, rarest, and brightest blue supergiant stars. Various types of main-sequence stars are given below.

This is called the r-process for 'rapid neutron capture,' which is believed to occur in supernovae. We can categorize them based on their colours and sizes. If the star is large enough and hot enough (core temperature above 15 million вЊ), the helium produced in nuclear fusion reactions will also be fused together to form heavier elements such as carbon, oxygen, neon, and finally iron.Д®lements heavier than iron, such as lead, gold, and uranium may be formed by the rapid absorption of neutrons, which then beta decay into protons.

Main sequence star chart