M
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d
ule
3 :
F
orm
a
tion of
S
t
a
rs
THE FIRST STARS IN THE UNIVERSE
- the first stars were massive and
luminous that their formation led to
the production and dispersion of
heavier elements, which led to the
formation of the solar system today
- density fluctuation left over from the
big bang could have evolved into the
first stars
-observations of distant quasars
allowed scientists to catch a glimpse
of the final days of the cosmic dark
ages
Quasars (Quasi-stellar radio sources)
- luminous and far celestial objects in
the universe that are detected due
the large electromagnetic radiation
that they emit
- They are thought to be powered by
supermassive black holes at the
centers of galaxies
PROTOGALAXIES
- the star-forming system is much
smaller and less organized than the
modern galaxy
- does not contain significant amounts
of any elements besides hydrogen
and helium.
- protogalaxies merge to form
galaxies and would gather into
galaxy clusters
Jeans mass
- minimum mass that a clump of gas
must have to collapse under its
gravity
FORMATION OF PROTOGALAXIES
- clouds of gas and dust that slowly
aggregate to form more matter
- as they evolve, they will begin to
merge and form larger structures like
the galaxy that we know today
HOW ARE STARS FORMED?
- From a cloud of dust and hydrogen
gas called nebuli
- The life of a star begins as a
protostar.
- Hydrogen molecules in these clouds
begin to react with one another to
form helium gas through the process
called thermonuclear fusion
- With enough mass and hugs amount
of energy the protostar eventually
collapses into its own gravitational
force and forms a hot ball of gas
Protostar
- Hot core formed from the collection
of dust and gas
Accretion
- Growing of protostar by absorbing
more material from its surroundings.
- Results in the increase of
temperature and density.
● Hydrogen molecules in these clouds
begin to react with one another to
form Helium gas through the
