Life and Death of a Star
How long a star lives depends on how long the star takes to use the hydrogen in its core.
Stars that are small or average in mass, such as the sun, shine for about 10 billion years. The
most massive stars live for only about one million years because they use up their hydrogen
A stars that is 10 to 30 times
more massive than the sun
spend most of its life as a
blue star. It glows blue for
about 1 to 20 million years.
A small or mid-sized star
like the sun spends most of
its life as a yellow star for
about 10 billion years.
Like a red giant, the star
because the star is so
massive, fusion continues
more steadily. A supergiant
Once a star has changed all the hydrogen into
helium, the outward force caused by fusion no
longer balances the inward pull of gravity. The
star begins to collapse. Then helium nuclei fuse
into move massive elements such as carbon.
The energy produced by this fusion expands.
The star’s surface. The star becomes a bigger,
cooler red giant. This change won’t happen to
the sun for another 5 billion years.
The supergiant continues
to swell. Then gravity pulls
the outer parts of the star
toward the center.
Pressure and temperature
increase so much that the
The red giant collapses as
again pulls the outer parts
of the star toward the
center. Pressure and
temperature increase. The
outer layers of the star
expand to form a nova.
The star in the center of
the nova continues to
collapse. It becomes a hot,
dense, white star called a
When a white dwarf uses
up its energy, it becomes a
dark, dense star that no
longer shines---a black
Structure : Subject and verb Agreement
Two singular subjects connected by“ or ” require a singular verb.
A small or mid – sized starlike the sun spends most of its life as a
As a general rule, use a plural verb with two or more subject when they are
connected by “and”
Pressure and temperature increase.
- Subject is singular, verb is also singular s, es
Example : The star is so massive.
- Subject is plural, verb is also plural.
Example :They use up their hydrogen more quickly.
Subject which is always plural form such as nuclei.
Then helium nuclei fuse into more massive element such as carbon.
[n.]a very large star of high luminosity and
low surface temperature. Red giants are
thought to be in a late stage of evolution
when no hydrogen remains in the core to
fuel nuclear fusion.
[n.]Star that suddenly becomes much
brighter for a short period.
[n.]a small very dense star that is typically
the size of a planet. A white dwarf is formed
when a low-mass star has exhausted all its
central nuclear fuel and lost its outer layers
as a planetary nebula.
[n.]A small or mid-sized star like the sun
spends most of its life as a yellow star.
[n.]A star that it 10 to 30 times more
that the sun spends most of
its life as a blue star.
[n.]a very large star that is even brighter
than a giant, often despite being relatively
[n.] a star that suddenly increases greatly
in brightness because of a catastrophic
explosion that ejects most of its mass.
[n.]Astronomy a cloud of gas and dust in
outer space, visible in the night sky
either as an indistinct bright patch or as a
dark silhouette against other luminous
[n.] Is a type of staller remnant that
result from the gravitational collapse of a
massive star during Type II, Type Ib or
Type Ic supernova event.
[n.] a region of space having a
gravitational field so intense that no
matter or radiation can escape.
[n.]the apportionment of financial liability
resulting from loss of or damage to a ship or
[v.]connected with the way people or
things seem to be rather than with what
is actually true.
[n.] is a with symbol He and atomic
numberIts boiling and melting points are
the lowest among the elements and it
exists only as a gas except in extreme