Our Sun is a main sequence star - Edexcel - GCSE Physics - Question 2 - 2015 - Paper 1

The formation of our Sun commenced in a nebula, primarily composed of gas and dust. Gravity plays a crucial role by pulling these particles together, which leads to the collapse of the nebula. As the nebula contracts, it forms a protostar.

As the protostar continues to gather mass, its temperature rises due to gravitational energy being converted into thermal energy. Eventually, when the core temperature reaches a sufficient level, nuclear fusion begins. This marks the transition from the protostar phase to the main sequence star phase where our Sun currently resides.