The Sun is a Rajshahi University's Geography and Environmental Studies Departments presentation.

1. The Sun
The Sun is the most prominent feature in our solar
system. It is the largest object and contains
approximately 98% of the total solar system mass.
One hundred and nine Earths would be required to fit
across the Sun's disk, and its interior could hold over
1.3 million Earths.
Age of sun is 4.603 billion years.
Sun is G2V type star, a yellow dwarf main sequence
star .

2. The Sun
Mass (kg) 1.989e+30 Mass (Earth = 1) 332,830
Equatorial radius (km) 695,508 Equatorial radius (Earth = 1) 108.97
Mean density (gm/cm3) 1.409 Mean density (Earth=1) 1/4
Rotational period (days) 25-36* Orbital velocity (km/sec) 230
Revolution (million years) 200 Luminosity (ergs/sec) 3.827e33
Magnitude (Vo) -26.8 Mean surface temperature 5500°C
Conversion rate 600 (m. metric ton/sec) Energy 3.83e+26 (Watts)
Average distance from Earth 150 m Km
* The Sun's period of rotation at the surface varies from approximately 25
days at the equator to 36 days at the poles. Deep down, below the convective
zone, everything appears to rotate with a period of 27 days.

3. Principal chemistry
Hydrogen 71%
Helium 27%
Oxygen 0.061%
Carbon 0.030%
Nitrogen 0.0084%
Neon 0.0076%
Iron 0.0037%
Silicon 0.0031%
Magnesium 0.0024%
Sulfur 0.0015%
All others 0.0015%

4. Principal Internal Balance (Hydrostatic Equilibrium)
The structure of the Sun depends on a balance between its internal
forces. One force holds the Sun together. A second force prevents the
Sun from collapsing. This balance is technically called hydrostatic
equilibrium. The Sun’s inward force arises from its own gravity. The
outward force arises from the rapid motion of its atoms, a motion that
gives rise to a pressure. Thus, in the Sun, as in virtually all stars and
planets, the balance of hydrostatic equilibrium requires that the outward
force created by pressure exactly balance the inward force of the Sun’s
gravity. Without such a balance, the Sun would rapidly change. For
example, if its pressure were too weak, the Sun’s own gravity would
rapidly crush it. Therefore, to understand the Sun, we need to discuss in
more detail how its pressure arises.

5. Principal Internal Balance (Hydrostatic Equilibrium)
A sketch illustrating the condition of
hydrostatic equilibrium, the balance of
pressure (blue arrows) and
gravitational force (purple arrows) in
the Sun.
Sketch illustrating the perfect, or ideal, gas law. Gas atoms move
faster at the higher temperature, so they collide both more
forcefully and more often than atoms in a cooler gas. These effects
combine to create a higher pressure. Thus, other things being
equal, a hotter gas exerts a greater pressure.

6. Interior structure of Sun
1. Core The Sun's energy comes from
thermonuclear reactions (converting
hydrogen to helium) in the core,
where the temperature is 15 to 25
million degrees. It covers 25% of Sun
radius.
2. Radiative zone The energy
radiates as photon through this
layer. It covers 50% of Sun radius.
3. Convective zone It covers 25% of
outer Sun radius. Then bubbles and
boils to the surface in a process
called convection. Charged particles,
called the solar wind, stream out at a
million miles an hour.

7. Interior structure of Sun

8. Sun spots
Magnetic fields within the sun
slow down the radiation of
heat in some areas, causing
sunspots, which are cool
areas and appear as dark
patches. Average temperature
is 3527
0
celcius. It’s diameter
is 50000 km.

9. Sun’s atmosphere
Photosphere
The lowest region of the sun’s atmosphere.
It can be seen from earth
300-400 km wide
Average temperature 5527 0 Celsius
Chromosphere
2000 km from photosphere to above
The middle layer of the sun’s atmosphere
Average temperature from 4226 to 9727 0
Celsius
Corona
The final or outer layer of the
sun’s atmosphere
From photosphere it extends
several million km
It can be seen best during the
solar eclipse
The average temperature 2
million degree celcius

10. Importance of Sun
Heat and light
Vegetation and animals
Solar energy
Solid and gasses
Minerals
Wind
Ocean current
Water cycle