Unusual Supernova Sheds Light on Heavier Element Fusion

The energy from stars, like our Sun, comes from a process called nuclear fusion. In the star’s core, hydrogen changes into helium, creating energy. A star can do this for millions or billions of years. When the hydrogen runs out, the star starts fusing helium into heavier elements like carbon and oxygen. It continues to change fuels until it reaches iron.

As these fusion processes happen, the star’s layers change. In older stars, the outer layer often has leftover hydrogen. Inside, there are layers of helium, carbon, and oxygen, ending with an iron core.

When the star runs out of silicon and sulfur, fusion stops. This happens because fusing iron and heavier elements does not create energy. Low-mass stars, like our Sun, stop shining and become cinders. Heavy stars go through a supernova, a powerful explosion. Gravity takes over, collapsing the star’s mass. The core becomes a neutron star or a black hole, while outer layers are blown away, possibly forming new stars or planets.

In 2021, a supernova named SN2021yfj surprised researchers. It showed all its layers had been expelled before exploding. Scientists are trying to understand how this happened.

How much do you know?

What process produces energy in stars like our Sun?

Nuclear fission

Nuclear fusion

Chemical reaction

Radioactive decay

What does hydrogen change into during nuclear fusion?

Oxygen

Helium

Carbon

Iron

What element does fusion stop at when a star runs out of silicon and sulfur?

Hydrogen

Helium

Carbon

Iron

What is the outcome for low-mass stars like our Sun when they stop shining?

They become black holes

They become neutron stars

They become cinders

They disappear completely

What is a supernova?

A type of hydrogen fusion

A powerful explosion of a heavy star

A form of neutron star

A layer of the sun

What did the supernova SN2021yfj show researchers?

It had leftover hydrogen

All its layers had been expelled before exploding

It became a black hole

It fused iron

Nuclear fusion can occur for only a few years in a star.

True False

Heavy stars undergo a supernova when they run out of fuel.

True False

The outer layers of older stars often contain helium.

True False

Low-mass stars like our Sun eventually form new stars.

True False

Fusing iron and heavier elements generates energy.

True False

SN2021yfj is a supernova that surprised researchers.

True False

The energy from stars comes from a process called nuclear .

When hydrogen runs out, the star starts fusing helium into elements.

The star's core becomes a neutron star or a black after a supernova.

In older stars, the outer layer often contains leftover .

When fusion stops, the core becomes an iron .

Gravity collapses the star's mass, leading to a powerful .

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