How Stars Die Flashcards
What is the evolution after the Main Sequence?
Yellow Main Sequence Star —> Red Giant Star —> Helium-core Burning Star —> Double Shell-Burning Red Giant —> Planetary Nebula —> White Dwarf
How do Planetary Nebula form?
When a star dies, it shed off its outer layers that causes cosmic gas and dust to form. The center is a White Dwarf.
What is a White Dwarf?
Core of a dying star that is extremely compact. (high mass; small size)
What are high mass stars? How do they differ from most stars?
High Mass Stars are very luminous yet short-living stars and have their own evolutionary path. (More and Much Faster process than other stars)
What is a High Mass Star’s Evolutionary Path?
- Massive Main-Sequence star burns hydrogen in core.
- Immediately begins burning helium in its core as it leaves main sequence.
- The ash of one reaction becomes fuel for the next as star evolves layered structure.
- This keeps occurring with different elements until a degenerate iron core is present; within onion-like shells of nuclear burning.
What is degenerate matter?
Absolute tightest arrangement of fermions (in stars, electrons) possible.
This is also called Electron Degeneracy Pressure.
Why is an iron core significant?
Iron cannot fuse; the core is dead
How does a Massive Star Supernova Explosion occur?
Gravity causes the iron core to collapse. This causes the iron core to neutralize and become one atom.
Then, a supernova explosion occurs !
What is left after a supernova explosion?
A very dense neutron star. (Ball of neutrons)
What is a White Dwarf?
Remains of a low mass star (degenerate and super dense)
The Chandrasekhar Limit
Mass Limit of White Dwarves: 1.44 Solar Mass
What happens when a White Dwarf exceeds the Chandrasekhar Limit?
The White Dwarf collapses, which pushes up temperature until carbon ignited and burns explosively.
This causes a SUPERNOVA ! which consumes the White Dwarf.
What are the two types of Supernovae?
Massive Star Supernovae
- Also known as Core Collapse Supernovae or Type II
White Dwarf Supernovae
- Also known as Type 1a; brighter than Type II Supernovae
What is a Binary System?
Two stars orbit around a common center of mass (gravitational bond together)
What is Cataclysmic Variable?
A binary system comprising of white dwarf and main-sequence star (typically low-mass)
