Stellar Evolution What is the fate of the sun and other stars??
Mar 27, 2015
Stellar EvolutionWhat is the fate of the sun
and other stars??
Formation of Stars• Begins with interstellar gas and dust called
a nebula• Collapses on self as a result of gravity• Rotates and flattens with hot condensed
object at center called a protostar
• When temperature becomes hot enough for nuclear fusion to occur Hydrogen (H) and Helium (He) are the first reaction.
Lifecycle of a Medium Star
• 10 % of a stars innermost mass react in nuclear fusion
• When H in core is gone, some left in outer layers
• Outer layers expand and cool; star becomes a Red Giant
• Red giants have low surface gravity, outer layers are driven away
• Core becomes hot enough to produce Carbon (C)
• Star contracts to normal size when helium is used up
• Carbon core left over, White dwarf remains
Lifecycle of Massive Stars• Massive stars undergo many reactions and
produce many elements• Cannot support themselves and violently
collapse on themselves
• Neutron Star – Collapse dense core of a star that forms quickly while its outer layers are falling inward
• Supernova – Massive explosion that occurs when the outer layer of a star are blown off
• Black Hole – Small, extremely dense remnant of a star whose gravity is so immense that even light can not escape its gravity field