Stars Flashcards
What factor determines the type of lifecycle a star
undergoes?
The size of the star
Which two phases do all stars of the same or greater
size than the sun undergo?
- Protostar phase
2. Main sequence phase
What do stars like the sun become at the end of their
life-cycle?
A black dwarf
What two things can stars much bigger than the sun
become at the end of their lifecycle?
- Neutron star
2. Black hole
What two phases do stars of similar size to the sun
go through between being a main-sequence star and
a black dwarf?
- Red giant
2. White dwarf
What two phases do stars of greater size than the
sun go through between being a main sequence star
and a neutron star/black hole?
- Red supergiant
2. Supernova
Describe the transition of the star from the nebula
stage to the main sequence
● The nebula increases in size until it is pulled in due to
its gravity, causing GPE to turn into KE
● The collisions between particles cause this kinetic
energy to turn into thermal energy
● Eventually the nebula will become dense and hot
enough to begin fusion
What occurs in the stage when a star is a main
sequence star?
● The fusion in the star releases energy ● This energy balances out with the gravitational potential energy leaving the star ● The star is in equilibrium so will not collapse due to gravity or expand due to radioactive behavior. It is stable.
What happens when a star transitions to the red
giant stage?
● Once all of the hydrogen fuel has been
used up, the star begins to fuse helium and
other
larger nuclei
● This causes the star to expand and become a
red giant
How does a red giant become a white dwarf and finally a black dwarf?
● Once all reactions have taken place, the star’s
gravity pulls in all of its mass, making a small,
dense white dwarf
● This will cool down to form a black dwarf
Why are telescopes located outside the earth’s
atmosphere?
● The earth’s atmosphere absorbs many
electromagnetic waves, making it difficult to detect
certain waves.
● Light pollution can make some images less clear
● Telescopes in space can operate both night and day
What is the disadvantage of telescopes located
outside the earth’s atmosphere?
They are difficult to maintain as they have
to be repaired in space (or brought down,
which is unreasonably expensive)
What are the disadvantages of optical telescopes?
● They can only be used at night when
the sky is clear
● They can’t be used when the weather
is cloudy etc.
Evaluate the use of radio telescopes
● They are not weather dependent for example
radio waves are not blocked by clouds so can
be used in the rain
● They are usually large and expensive
