Life cycle of stars
What is star?
• Hot gas and dust cloud
• Heat of stars made in Centre by nuclear fusion
• There are lots of different colours and sizes of star
• Some times we consider stars as our thatha patti…
Birth of stars
• Nebula is the birth place of the stars
• It has cloud of gas (hydrogen) and dust
• There are different types of nebula
• Eg : Emission nebula, planetary Nebula
and so on.
• As it the stellar materials pulls
tighter and tighter together. It
heats up pushing against further
gravitational collapse. At this point
the object is known as Protostar.
• The protostar phase of stellar
evolution lasts about 100,000 years
Main sequence Star
• A star is a luminous globe of gas producing its own
heat and light by nuclear fusion reaction.
• The surface temperatures range from 2000°C to
above 30,000°C , and the corresponding colors from
red to blue-white.
• They live for less than a million years before exploding
• This is the bright star with a
• It is formed during the Sun, as
it runs out of hydrogen fuel at
• These stars have diameters up
to 1000 times that of sun.
• These are very cool, faint
and small stars,
• They burn very slowly and
have estimated lifetimes of
100 billion years.
• This is very small and hot star
• It consist of degenerate matter
with a very high density due to
• The surface temp is 8000° C
• This is explosive death of
star, and often results in
the star obtaining the
brightness of 100 million
suns for a short time.
• These stars are composed mainly of
neutron and are produced when a
supernova explodes, forcing the
protons and electrons to combine to
produce a neutron star.
• Its gravity will be so strong.
• Black holes are believed to form from
massive stars at the end of their life times.
• The gravitational pull in a black hole is so
• The density of matter in a black hole cannot
• It distort the space around them, suck
neighboring matter into them including