2. What is Sun?
• The Sun is the star at the center of the Solar System.
• Major source of energy for earth.
• It is a nearly perfect sphere of hot plasma.
• It is heated by nuclear fusion reactions in its core.
• Heatning of plasma emit the energy mainly as visible light,
ultraviolet light, and infrared radiation.
3. Reaction on Sun
• Nuclear fusion type
reaction: Sun is fueled by
proton-proton cycle chain.
• It is sets of nuclear fusion
reactions by which stars
convert hydrogen to helium
4. Parts of Sun
There are thee major parts of sun
• The core
• The radiative zone
• The convective zone
5. Characteristics of Sun
• Surface temperature: 5,778 K
• Mass: 1.989 × 1030 kg
• Radius: 696,340 km
• Age: 4.603 billion years
• Distance to Earth: 149.6
million km
• Gravity: 274 m/s²
• Composition: 75%
hydrogen, 25% helium
• Volume of the Sun: 1.412 x
1018 km3
• Density of the Sun: 1.622 x
105 kg/m3
• Color: White
