Question

A star is born when clouds of dust and elements are gathered together in a certain space due to gravity, more and more mass and therefore pressure builds @Edmund1

Answer 1

Explain the steps of the life cycle of a star. Beginning with a nebula and ending with old age/death of a star, explain each step in a star’s life cycle.

Answer 2

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Answer 3

Stars are born in a region of high density Nebula, and condenses into a huge globule of gas and dust and contracts under its own gravity. A region of condensing matter will begin to heat up and start to glow forming Protostars. If a protostar contains enough matter the central temperature reaches 15 million degrees centigrade. At this temperature, nuclear reactions in which hydrogen fuses to form helium can start. The star begins to release energy, stopping it from contracting even more and causes it to shine. It is now a Main Sequence Star. A star of one solar mass remains in main sequence for about 10 billion years, until all of the hydrogen has fused to form helium. The helium core now starts to contract further and reactions begin to occur in a shell around the core. The core is hot enough for the helium to fuse to form carbon. The outer layers begin to expand, cool and shine less brightly. The expanding star is now called a Red Giant. The helium core runs out, and the outer layers drift of away from the core as a gaseous shell, this gas that surrounds the core is called a Planetary Nebula. The remaining core (thats 80% of the original star) is now in its final stages. The core becomes a White Dwarf the star eventually cools and dims. When it stops shining, the now dead star is called a Black Dwarf.