Download The Sun

The Sun
By: JGilliam
The Sun’s Composition
Identifying Stars
Composition
▪ Hydrogen and Helium together make up 99% of
the sun’s mass.
▪ Scientist break up the star’s light into spectra by
using a device called a Spectrograph.
▪ 75% of the sun’s mass is Hydrogen.
▪ Using these Spectra, scientist can identify the
certain elements that are present in a star’s
atmosphere.
▪ Mainly ionized gasses
Spectral Lines
▪ Scientist can also deduce the temperature, density,
and pressure of the gas.
▪ Because each element produces unique patterns of
spectral lines, scientist can match the spectral lines
of starlight to those of Earth’s elements, and
identify the elements in the star’s atmosphere.
Spectrograph
Nuclear Fusion in the Sun
▪ Nuclear Fusion: The process by which nuclei of small atoms combine to form a new, more massive nucleus; the
process releases energy. This occurs inside the sun.
▪ Fusion releases huge amounts of energy.
▪ Hydrogen atoms are the primary fuel for the sun’s fusion.
▪ Hydrogen atoms commonly consist of only one proton and one electron. However, electrons are stripped from
the protons by the Sun’s intense heat.
▪ During fusion a subatomic particle, called a neutrino, is given off. Neutrinos escape the sun and reach Earth in
about eight minutes. Studies of these particles indicate that the sun is fueled by fusion.
Key:
Protons – positive
Electrons – negative
Neutrons - neutral
Nuclear Fusion Steps
Nuclear Fusion consist of three steps

In the first step, two hydrogen nuclei, or protons,
collide and fuse. The positive charge of one of the
protons is neutralized as that proton emits a
particle called a positron. As a result the proton
become a neutron and changes the original two
protons into a proton-neutron pair.

In the second step, another proton combines with
the proton-neutron pair to produce a nucleus made
up of two protons and one neutron.

In the third step, two nuclei made up of two
protons and one neutron collide and fuse. As this
fusion happens, two protons are released. The
remaining two protons and one neutron fuse
together and form a helium nucleus.

Final Product- One of the final products of the
fusion of hydrogen in the sun is always a helium
nucleus. The helium nucleus has about 0.7% less
mass than the hydrogen nuclei that combined to
form it. The lost mass is converted into energy
during the series of fusion reactions that forms
helium. Because all nuclear fusion releases energy,
the three steps of nuclear fusion cause the sun to
shine and gives the sun it’s high temperatures.
The Sun’s Interior
The Core
▪ Makes up 25% of the sun’s total diameter.
▪ The Core’s temperature is about 15,000,000˚c. No solids or liquids can exist at such a high temperature
▪ Like the rest of the Sun the core is made up entirely of ionized gasses
▪ Because of the sun’s large mass, the pressure from the Sun’s material is so great that the core is more than ten
times as dense as iron.
▪ The enormous pressure and high temperature of the Sun’s core strip away electrons from the atomic nuclei.
Also, the conditions force positive nuclei to fuse.
The Radiative Zone
 Radiative zone: The zone of the Sun’s interior that is between the core and the convective zone and in which
energy moves by radiation.
 The temperature ranges from about 2,000,000˚c to 7,000,000˚c
 Energy moves outward in the form of electromagnetic waves or radiation.
The Convective Zone
▪ Convective zone: The region of the Sun’s interior that is between the radiative zone and the photosphere and in
which energy is carried upward by convection.
▪ The temperature is about 2,000,000˚c.
▪ Energy moves through this zone by convection.
The Sun’s Atmosphere
The Photosphere “ Sphere of Light”
▪ Photosphere: The visible surface of the sun.
▪ Made up of the gasses that have risen from the Convective zone.
▪ The temperature is about 6,000˚c
▪ Referred to as the Sun’s surface because this layer is the visible surface of the Sun.
The Chromosphere “Color Sphere”
▪ Chromosphere: The thin layer of the sun that is just above the photosphere and that glows a reddish color
during eclipses.
▪ A thin layer of gasses that glows with reddish light that is typical of the color given off by Hydrogen
▪ The temperature ranges from 4,000˚c to 50,000˚c
▪ The gasses of the Chromosphere move away from the photosphere
▪ In upward motion, gas regularly forms narrow jets of hot gas that shoot outward to form the Chromosphere and
then fade away within a few minutes. Some of these jets can reach heights of 16,000km
The Corona “Crown”
▪ Corona: The outermost layer of the sun’s atmosphere.
▪ A huge region of gas that has a temperature above 1,000,000˚c
▪ It is not very dense, but it’s magnetic field can stop most subatomic particles from escaping into space
▪ Ions do escape as the Corona expands. These particles make up the solar wind which flows outward from the
sun to the rest of the solar system.
The Transition Region
▪ Just above the Chromosphere is a thin zone called the transition region where the temperature rises dramatically.
The Sun
Size: Diameter of 1,390,000km; 218.4x Earth’s
Color: Generally a orange/yellow color
Features: Sunspots
Rotation: Equator – 25.3 days
Poles – 33 days
Density: 1.409 g/cm³: 0.256 that of Earth’s
Gravity: 274.0 m/s²; 27.96x Earth’s
Atmosphere: Mostly gasses that have risen off the Convective Zone
Surface: Energy moves through the Convective Zone and outward; made up of ionized gasses
Interior: No liquids or solids can exist in the interior. Made up of ionized gasses
Magnetic field: Unidentified
Moons: None
Unique: 4.6 billion years old
Fin