Final answer:
The life cycle of stars begins in a molecular cloud and progresses through the main sequence phase during which a star spends most of its life. Low-mass stars evolve into red giants and then white dwarfs, while high-mass stars typically end in a supernova, leaving neutron stars or black holes.
Step-by-step explanation:
The Formation and Death of Stars
Stars undergo a complex process of formation and evolution before they reach the end of their life cycle. The formation of a star begins in a dense region within a molecular cloud, where the core material gravitationally collapses to form a protostar. This young star then gradually accretes more matter, increasing its mass and temperature until the internal pressure and temperature are sufficient for nuclear fusion to commence in its core. This marks the arrival of the star on the main sequence, where it will spend most of its life stably burning hydrogen into helium.
In the final stages of a star's life, it exhausts its nuclear fuel. Low-mass stars, like our Sun, swell into red giants, shedding outer layers and eventually leaving behind a white dwarf. More massive stars meet an explosive end in a supernova, possibly resulting in the formation of neutron stars or black holes, and sending shock waves through the cosmos.
The life cycle of stars is a key concept in astrophysics, and understanding it requires observations of numerous stars at different stages of their lives, collectively known as a 'stellar census'. The evolution differs between high-mass stars and low-mass stars, with the former tending toward more violent finales.