What Is the Sun Made Of

1
What Is the Sun Made Of?
2
Discovery of Dark Lines

• Wollaton (1802) and Fraunhofer (1817) noticed
  dark lines in the continuous spectrum of the sun
• These are now called Fraunhofer Lines and are
  labeled with letters

3
Internal Structure of the Sun

• The core is where nuclear fusion takes place
  (27,000,000 F)
• The radiative zone is the inner two thirds of the
  sun
• Energy travels by radiation
• The convection zone makes up the outer third of
  the sun
• Energy travels by convection

4
Energy Production

• Energy is created in the core of the sun through
  nuclear fusion squeezing Hydrogen (1 proton) so
  much it fuses into Helium (2 protons) and then
  other elements
• E mc2 ? this creates energy

5
External Structure of the Sun

• Chromosphere (1200 1900 miles thick, 17500F -
  9950F)
• Heated by the core
• Photosphere (200 miles thick, 9950F)
• Creates the absorption lines you see when light
  passes through it on its way to Earth
• Corona (extends to Earth, 4 million degrees F)
• Heated by suns magnetic field rather than the
  core
• Solar Wind (outer corona)
• Fast Wind 470 miles/sec
• Slow Wind 190-250 miles/sec

6
The Corona
7
Lines and Elements
8
Effective Temperature

• We can measure the flux received by the Earth
  from the sun
• The solar constant is 1353 watts/m2
• Flux sT4
• s is called Boltzmanns constant
• Tsun 5800K 9980F
• Thats about the temperature of the photosphere!

9
How Can We Do This Without Math?

• Hot stars look blue or white
• Cool stars look orange or red
• We can estimate a stars temperature by looking
  at the color where most of its light occurs

10
Sunspots

• There are sometimes parts of the photosphere that
  are cooler than others
• These spots look darker against the rest of the
  hotter material
• ? Sunspots!

11
The Sun Right Now!

• Current Solar Image from Catania Astrophysical
  Observatory (Italy)

12
A Few More Pictures
13
Basic Lab Procedure

• I have a video of the solar spectrum we will be
  viewing
• Well go through the manual together and answer
  each question using the video and other knowledge
• Be sure to fill out the blank spectrum and solar
  disk diagrams!