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ASTA01H3 Lecture Notes - Positron

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Rick Halpern

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Lecture 23: The Sun
o1.3 Million earth would fit in the sun
oRotation is differential
oPeriod is about a month
oSurface temperature is 5780K
oSurface visible is called photosphere
o91% hydrogen, 7.8% helium
oSun extends beyond photosphere
oInterior of the sun
oCore is where nuclear fusion takes place
oWe are able to look through the Corona, Transition Zone and Chromosphere
oLuminosity total energy radiated by the Sun per unit time
oSuns total luminosity = = 10 billion 1 megaton nuclear bombs per second
Solar constant amount of Suns energy reaching Earth is 1400 W/m2
oEvery kg of the Sun produces 0.2 milliwatts of energy
This will continue through 10 billion years producing 3x10^13 J/kg
oNuclear fusion
Nucleus 1 + nucleus 2 nucleus 3 + energy
Mass turned into energy E=mc2
oLike-charged nuclei get close enough to fuse eachother
Only happens in high temperature over 10 million K
Proton + proton deuteron + positron + neutrino
Positron is like electron but positive charge
Neutrino has no charge and very little mass
Positron is anti matter. It is annihilated by collision with an electron
resulting in a gamma ray
Second step is formation of isotope of helium
Final step: 2 helium -3 isotopes forms helium 4 and energy
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