Solar Astronomy

Question 1

Facts about the sun

Answer 1

Sun is our nearest star
Bag standard G2 Dwarf star - one of billions in our galaxy
Diameter is approximately 1.4 million km across
You could fit about 1.3 Million Earths inside the sun
Surface temp is 5700 Kelvin (K)

Question 2

Internal structure of the Sun - Core

Answer 2

•Core - 15,000,000 Kelvin - Energy produced through nuclear fusion of Hydrogen Nuclei into Helium Nuclei (proton proton chain)

Question 3

Internal structure of the Sun - Radiative Zone

Answer 3

• Radiative Zone - 7,000,000 to 2,000,000 Kelvin - Gamma ray photons are scattered about like pinballs transferring energy slowly upwards

Question 4

Internal structure of the Sun - Convective Zone

Answer 4

•Convective Zone - 2,000,000 to 5800 Kelvin - Pockets of hot gas rise and cool, releasing their energy into the photosphere through convection.

Question 5

Internal structure of the Sun - Photosphere

Answer 5

•Photosphere - 5800 Kelvin - Photons of mainly UV and visible light leave the surface and carry energy out into space.

Question 6

Internal structure of the Sun - Chromosphere

Answer 6

•Chromosphere - 20,000 Kelvin - Thermal energy transfer via the Sun’s magnetic field.

Question 7

Internal structure of the Sun - Corona

Answer 7

•Corona - 2,000,000 Kelvin - Thermal energy transfer via the Sun’s magnetic field.

Question 8

Proton Proton Chain

Answer 8

1. Smash two protons together to make deuterium
2. A proton crashes into a deuterium nucleus, making helium-3
3. Mash two helium-3 nuclei together to make helium-4

Question 9

Proton Proton Chain

Answer 9

1. Proton + Proton -> Deuterium + positron + neutrino
2. Deuterium + proton -> helium -3 + gamma ray photon
3. Helium -3 + helium -3 –> helium -4 + 2 protons
   1 H + 1 H -> 2 H + E+ ν
4. 2 H + 1 H –> 3 He + γ
5. 3 He + 3 He –> 4He + 1 H + 1 H

Question 10

Sunspots

Answer 10

Umbra (4000K)
Penumbra (5600K)
Always comes in pairs.

Question 11

Safely observing the sun

Answer 11

Safely observing the sun:

1. Solar projection - Good - cheap, lots of people can see sun at same time
2. Bad - Can damage delicate parts of the telescope. Hard to see detail on image of the sun

Question 12

Safely observing the sun

Answer 12

2. Hi Alpha Filter
Good - can see fine detail 
Less chance of damage to telescope 
Safer
Bad - can only be viewed by one person at a time
Can be very expensive

Question 13

The Van Allen Belts

Answer 13

Outer Allen Belts - 15,000 to 65,000KM from earth.
Consists primarily of electrons (e-)
Inner Allen belts - 1500 to 10,000KM
Consists mainly of protons.

Question 14

What is responsible for forming the ion tail of a comet?

Answer 14

Charged particles in the solar wind

Question 15

What is the approximate temperature difference between the central umbra of a sunspot and the sun’s photosphere?

Answer 15

2000 Kelvin

Question 16

In the formula E = mc² , what does c refer?

Answer 16

speed of light

Question 17

Which of the following is not caused by the solar wind?
Aurorae
geomagnetic storms
high and low tides
ion tails of comets

Answer 17

high and low tides