1	Chapter 13 The Bizarre Stellar Graveyard
2	White Dwarfs... ...are stellar remnants for low-mass stars. ...are found in the centers of planetary nebula. ...have diameters about the same as the Earth’s. ...have masses less than the Chandrasekhar mass.
3	Sirius B is a white dwarf star
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5	Novas and Supernovas Nova - a stellar explosion Supernova - a stellar explosion that marks the end of a star’s evolution White Dwarf Supernova (Type I supernova)- occur in binary systems in which one is a white dwarf Massive Star Supernova (Type II Supernova) - occur when a massive star’s iron core collapses
6	Close Binary Systems and Mass Transfer
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12	Type II Supernova The star releases more energy in a just a few minutes than it did during its entire lifetime. Example: SN 1987A After the explosion of a massive star, a huge glowing cloud of stellar debris - a supernova remnant - steadily expands. Example: Crab Nebula After a supernova the exposed core is seen as a neutron star - or if the star is more than 3 solar masses the core becomes a black hole.
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15	Type I and Type II Supernova
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19	Carbon Burning and Helium Capture
20	Still heavier elements are created in the final stages of life of massive stars
21	Alpha Process – Helium Capture produces heavier elements up to Fe and Ni.
22	Elements beyond Fe and Ni involve neutron capture.
23	"The supernova explosion then distributes..." The supernova explosion then distributes the newly formed matter throughout the interstellar space (space between the stars). This new matter goes into the formation of interstellar debris. The remnant core is a dense solid core of neutrons – a neutron star!
24	Neutron Stars ...are stellar remnants for high-mass stars. ...are found in the centers of some type II supernova remnants. ...have diameters of about 6 miles. ...have masses greater than the Chandrasekhar mass. (1.4M₈)
25	Relative Sizes
26	Pulsars The first pulsar observed was originally thought to be signals from extraterrestrials. (LGM-Little Green Men was their first designation)
27	"It was later shown to..." It was later shown to be unlikely that the pulsar signal originated from extraterrestrial intelligence after many other pulsars were found all over the sky.
28	Pulsars The pulsing star inside the Crab Nebula was a pulsar. Pulsars are rotating, magnetized neutron stars.
29	The Crab Nebula
30	The Crab Pulsar
31	Light House Model Beams of radiation emanate from the magnetic poles. As the neutron star rotates, the beams sweep around the sky. If the Earth happens to lie in the path of the beams, we see a pulsar.
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35	Rotation Rates of Pulsars The neutron stars that appear to us as pulsars rotate about once every second or less. Before a star collapses to a neutron star it probably rotates about once every 25 days. Why is there such a big change in rotation rate? Answer: Conservation of Angular Momentum
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38	Mass Limits Low mass stars Less than 8 M_¤ on Main Sequence Become White Dwarf (< 1.4 M_¤) Electron Degeneracy Pressure High Mass Stars Less than 100 M_¤ on Main Sequence Become Neutron Stars (1.4M_¤ < M < 3M_¤) Neutron Degeneracy Pressure
39	Black Holes ...are stellar remnants for high-mass stars. i.e. remnant cores with masses greater than 3 solar masses …have a gravitational attraction that is so strong that light cannot escape from it. …are found in some binary star systems and there may be super-massive black holes in the centers of some galaxies.
40	Supermassive Stars If the stellar core has more than three solar masses after supernova, then no known force can halt the collapse
41	In general Relativity, space, time and mass are all interconnected
42	Space-Time
43	Predictions of General Relativity Advance of Mercury’s perihelion Bending of starlight
44	Advance of Mercury’s Perihelion
45	Bending of Starlight
46	Schwarzschild Black Hole
47	Near a Black Hole
48	What Can We Know? Mass gravity Charge Electric Fields Rotation Rate Co-rotation
49	How Can We Find Them? Look for X-ray sources Must come from compact source White Dwarf Neutron Star Black Hole Differentiate by Mass WD - < 1.4 M_¤ NS - between 1.4 and 3 M_¤ BH - > 3 M_¤
50	Cygnus X-1
51	End of Chapters
52	End of Section.
53	Nucleosynthesis
54	Energy Budget
55	Anazasi Pictographs
56	Supernova 1998S in NGC 3877
57	Supernova Remnants
58	PSR 0628-28
59	LGM? Several more found at widely different places in the galaxy Power of a power equals total power potential output of the Earth No Doppler shifts
60	Light Time Argument An object which varies its light can be no larger than the distance light can travel in the shortest period of variation.
61	To Darken the Sun
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63	Pulse Mechanisms Binary Stars - How quickly can two stars orbit? Two WD about 1^m Two NS about 1^s. Neutron Stars in orbit should emit gravity waves which should be detectable. Oscillations - Depends only on density WD about ten seconds NS about .001^s Little variation permitted. Rotation - Until the object begins to break up. WD about 1^s NS about .001^s with large variation.
64	SS 433
65	Synchrotron Radiation
66	Glitches