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 more quickly.

Nebula

Mid-Sized Stars

A small or mid-sized star like the sun spends most of its life as a yellow star for about 10 billion years.

Massive Stars

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.

Red Giant

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.

Supergiant

Like a red giant, the star expands. However, because the star is so massive, fusion continues more steadily. A supergiant forms.

Nova

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.

Supernova

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 star explodes---supernova

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Supernova Nova

White Dwarf

The star in the center of the nova continues to collapse. It becomes a hot, dense, white star called a white dwarf.

Black Dwarf

When a white dwarf uses up its energy, it becomes a dark, dense star that no longer shines---a black dwarf.

Black Hole Neutron Star

Structure : Subject and verb Agreement

Rule 1

Two singular subjects connected by “ or ” require a singular verb.

Example :

A small or mid – sized star like the sun spends most of its life as a yellow star.

Rule 2

As a general rule, use a plural verb with two or more subject when they are connected by “and”

Example :

Pressure and temperature increase.

Rule 3

Present simple

- 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.

Rule 4

Subject which is always plural form such as nuclei.

Example :

Text 2

Then helium nuclei fuse into more massive element such as carbon.

Vocabulary

[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.

Text 1

red giant

Nova

white dwarf

Mid-sized star

massive star

[n.]A star that it 10 to 30 times more massive 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 cool.

[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 matter.

[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.

supergiant

Supernova

Nebula

Neutron star

Black hole

[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 its cargo.

[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 number Its boiling and melting points are the lowest among the elements and it exists only as a gas except in extreme conditions.

Average

out ward

helium