Space Physics Flashcards
State the life cycle of stars about the same size as the Sun
Nebula → Protostar → Main Sequence Star → Red Giant → White Dwarf → Black Dwarf
State the life cycle of stars much bigger than the Sun
Nebula → Protostar → Main Sequence Star → Red Super Giant → Supernova → Neutron Star OR Black Hole
Where do stars form from?
A cloud of dust and gas (nebula)
What are nubelas known as, and what is meant by this term?
Stellar nursery = where stars are born
How is a protostar formed?
Force of gravity pulls dust and gas together to form protostar (+ temperature increases until hydrogen can fuse)
How is a main sequence star formed from a protostar?
- Star gets denser = temperature rises + more particles collide
- When temp. high enough = hydrogen nuclei undergo nuclear fusion to form helium nuclei (in core)
- Gives out huge amounts of energy = keeps core of star hot → star born
What is meant by a main sequence star entering a long stable period?
Outward pressure (caused by nuclear fusion) trying to expand star balances force of gravity pulling everything inwards
How does a main sequence star become a red giant or red super giant?
- Eventually, hydrogen runs out = begins to fuse with heavier elements
- ∴ Star swells into red giant or red super giant
Name 3 things that occur in red giants/red super giants
- Fusion of helium occurs
- Heavier elements up to iron are created in core of star
- (Becomes) red because surface cools
How does a red giant become a white dwarf?
- Red giant becomes unstable (bc run out fuel + can’t fuse) = eject its outer layer of dust and gas
- Leaves behind hot, dense, solid core → white dwarf
- Glows white hot = extremely hot
How does a white dwarf become a black dwarf?
- White dwarf cools down = emits less energy
- When no longer emits a lot = Black Dwarf
What is a black dwarf a theory?
Haven’t seen a white dwarf cool down = haven’t been enough time from Big Bang
What happens in the core of a star?
- Where temp. + density highest
- Where most nuclear fusion takes place
The more massive a star…
the hotter its core and the heavier the nuclei it can create by fusion
Explain how a red super giant turns into a supernova
- Glow brightly again → undergo more fusion and expand and contact several times
- Form elements as heavy as iron in nuclear reactions
- Eventually, they’ll explode in supernova
- Forming elements heavier than iron and ejecting them into universe to form new plants & stars
Stars & their life cycles produce and distribute …
all naturally occurring elements
Explain how supernova turns into a neutron star
Exploding supernova throw outer layers of dust and gas into space = leaving very dense core → neutron star