SOLAR SYSTEM

Detailed explanation-1: -Stars are fueled by the nuclear fusion of hydrogen to form helium deep in their interiors.

Detailed explanation-2: -Main sequence stars are characterised by the source of their energy. They are all undergoing fusion of hydrogen into helium within their cores.

Detailed explanation-3: -A star is a really hot ball of gas, with hydrogen fusing into helium at its core. Stars spend the majority of their lives fusing hydrogen, and when the hydrogen fuel is gone, stars fuse helium into carbon.

Detailed explanation-4: -When the stars go out. Eventually, a main sequence star burns through the hydrogen in its core, reaching the end of its life cycle.

Detailed explanation-5: -Stars evolve because of changes in their composition (the abundance of their constituent elements) over their lifespans, first by burning hydrogen (main sequence star), then helium (horizontal branch star), and progressively burning higher elements.

Detailed explanation-6: -Most of the energy from a main sequence star is created by fusing hydrogen in a process known as the Proton-Proton Chain Reaction. This reaction takes hydrogen atoms, which have a single proton and combines them into helium atoms, which have two protons and two neutrons.

Detailed explanation-7: -A star is a huge glowing ball of hot gas. Deep inside its core, hydrogen atoms smash together, forming helium and releasing huge amounts of energy that heats the gas. This is called nuclear fusion, and it’s why a star shines. As the hot gas pushes outward, it opposes the inward pull of gravity.