P630 Nuclear AstrophysicsP630 Nuclear Astrophysics

Charles HorowitzCharles Horowitz Fall 2002, Indiana UniversityFall 2002, Indiana University Course Web site: Course Web site:

http://cecelia.physics.indiana.edu/p6http://cecelia.physics.indiana.edu/p630/index.html30/index.html

What is the Universe made of? Why What is the Universe made of? Why is it this way?is it this way?

Note, nucleosynthesis today, discuss Note, nucleosynthesis today, discuss neutrinos later.neutrinos later.

Supernova Simulation by Burrows Supernova Simulation by Burrows and Foxand Fox

SN Simulation by E. Marietta. SN Simulation by E. Marietta.

Exploding Star Exploding Star is just above is just above frame and frame and interacts with interacts with its binary its binary companion companion starstar

Nuclear Reaction Network Nuclear Reaction Network Simulation by B. MeyerSimulation by B. Meyer

Burning Burning of Si of Si shell to shell to Ni -> Fe Ni -> Fe as SN as SN shock shock passes passes throughthrough

Vela

Cas ACas A Chandra X-ray Chandra X-ray

Observatory image of Observatory image of the supernova the supernova remnant Cassiopeia A remnant Cassiopeia A shows low, medium shows low, medium and high energy X-and high energy X-rays (red, green and rays (red, green and blue)blue)

Red is enriched in Fe, Red is enriched in Fe, bright greenish white bright greenish white region in lower left region in lower left enriched in silicon and enriched in silicon and sulfur.sulfur.

AbundancesAbundances

From meteorites and solar spectraFrom meteorites and solar spectra Meteorites are relatively unchanged Meteorites are relatively unchanged

since being formed 4.6 B years ago since being formed 4.6 B years ago with the solar system.with the solar system.

Abundances reflect composition of Abundances reflect composition of primitive solar nebula at time of primitive solar nebula at time of formation. formation.

Heavy elements made in previous Heavy elements made in previous generation stars. Not made in Sun.generation stars. Not made in Sun.

Most Abundant NucleiMost Abundant Nuclei

NucleusNucleus AbundanceAbundance SourceSource

1HH 0.7060.706 Big BangBig Bang

44HeHe 0.2750.275 Big Bang, CNO, Big Bang, CNO, pppp

1616OO 0.00960.0096 HeliumHelium

2020NeNe 0.00150.0015 CarbonCarbon

5656FeFe 0.00120.0012 e-processe-process

1414NN 0.00110.0011 CNOCNO

2828SiSi 0.00070.0007 OxygenOxygen

Astrophysical NeutrinosAstrophysical NeutrinosDear Radioactive Ladies and Gentleman,Dear Radioactive Ladies and Gentleman,

……because of the “wrong” statistics of because of the “wrong” statistics of 1414N and N and 66Li nuclei and the Li nuclei and the continuous beta spectrum, I have hit upon a desperate remedy to continuous beta spectrum, I have hit upon a desperate remedy to save the “exchange theorem” of statistics and the conservation of save the “exchange theorem” of statistics and the conservation of energy. Namely the possibility that there exists in nuclei energy. Namely the possibility that there exists in nuclei electrically neutral particles, that I call neutrons, which have spin electrically neutral particles, that I call neutrons, which have spin ½… The mass of the neutrons should be of the same order as the ½… The mass of the neutrons should be of the same order as the electron mass and in any event not larger than 0.01 proton electron mass and in any event not larger than 0.01 proton masses. The continuous beta spectrum would then be explained masses. The continuous beta spectrum would then be explained by the assumption that in beta decay a neutron is emitted in by the assumption that in beta decay a neutron is emitted in addition to the electron such that the sum of the energies of the addition to the electron such that the sum of the energies of the electron and neutron is constant.electron and neutron is constant.

I agree that my remedy should seem incredible because one I agree that my remedy should seem incredible because one should have seen those neutrons very earlier if they really exist. should have seen those neutrons very earlier if they really exist. But only the one who dare can win and the difficult situation… But only the one who dare can win and the difficult situation… Thus dear radioactive people, look and judge. Unfortunately, I Thus dear radioactive people, look and judge. Unfortunately, I cannot appear in Tubingen since I am indispensable here in Zurich cannot appear in Tubingen since I am indispensable here in Zurich because of a ball on the night of 6/7 December.because of a ball on the night of 6/7 December.

Your humble servant, W. PauliYour humble servant, W. Pauli Dec. 4, 1930 Dec. 4, 1930

Solar Neutrino SpectrumSolar Neutrino Spectrum

Sudbury Sudbury Neutrino Neutrino

ObservatoryObservatory

SNO Under construction excavating a large cavity

Underground neutrino detectorsUnderground neutrino detectors Superkamikonda is a giant Superkamikonda is a giant

tank with 32000 tons of tank with 32000 tons of very clean water. very clean water.

This is deep in a mine to This is deep in a mine to protect from cosmic rays. protect from cosmic rays.

Very rarely a neutrino will Very rarely a neutrino will interact and cause a small interact and cause a small flash of light in the tank.flash of light in the tank.

Phototubes on the walls Phototubes on the walls detect these flashes of detect these flashes of light.light.

SK should detect a few SK should detect a few thousand neutrinos from a thousand neutrinos from a galactic supernova.galactic supernova.

20 Events from SN1987A20 Events from SN1987A

The anti-nu appear to be cooling with time not getting warmer.