3. White Dwarfs
Definition: The remnant of a star that has collapsed, having
an extremely dense state with no empty space between its
atoms, but not reaching the extremely dense state of a
neutron star or black hole.
• They are burned-out
cores.
• Extremely low hydrogen.
•Carbon and oxygen.
• Electron degeneracy
pressure.
4. White Dwarfs
• Very dense (mass ≈ Sun ’s
mass).
• Very small (size ≈ The
Earth ’s size).
• Faint(1) luminosity.
• Sirius B is the nearest.
(1)
Faint: not strong
• Over 97% of the stars in
the Milky Way.
5. Neutron stars
Definition: An
extremely compact ball
of neutrons created
from the central core
of a star that collapsed
under gravity during a
supernova explosion.
• Very hot.
• Quantum degeneracy pressure.
• Calvera, Ursa Minor.
6. Neutron stars
• Extremely small.
• Extremely high mass.
• Protons + electrons Neutrons
• Blinking radiation Pulsars
• Non-spinning Normal neutron stars
• Very high pressure.
Editor's Notes
The first thing we have to say is when a star becomes a neutron star or a white dwarf. As we can see on this picture, they are steps in a star life that come right after the collapse or death of the star. When a star dies, it can turn into 3 different things, two of them are a white dwarf and a neutron star and the other one is a black hole. Also white dwarfs will eventually become black dwarfs.
White dwarfs can be defined as the remnant of a star that has collapsed, having an extremely dense state with no empty space between its atoms, but not reaching the extremely dense state of a neutron star or a black hole.
They are the burned-out cores of collapsed stars that slowly cool. They have burned up all of the hydrogen they once used as nuclear fuel so their mass is based on carbon and oxygen. There is no nuclear fusion in a white dwarf. Instead, the force that opposes gravity is called "electron degeneracy pressure".
White dwarfs have very high masses whereas their size is similar to the Earth’s size. They have faint luminosity that comes from the emission of stored thermal energy. The nearest white dwarf is Sirius B and over 97% of the Milky Way Stars are white dwarfs.
Neutron stars are extremely compact balls of neutrons created from the central core of a star that collapsed under gravity during a supernova explosion. They are very hot and they have something called Quantum degeneracy pressure that prevents the star from collapsing even more. The nearest neutron star is Calvera in Ursa Minor.
Despite their small diameters (about 20 km), neutron stars have between twice and 3 times the mass of our Sun. Only a teaspoonful of a neutron star would weigh about 100 million tons on Earth. This density causes protons and electrons to combine into neutrons. These stars have a very high gravity strength and also rotate as the Earth’s rotation movement but higher.
Neutron stars emit radiation which, seen from Earth, seems to blink on and off as the star spins. These neutron stars are called Pulsars. However, Pulsars will eventually stop spinning and they will become normal neutron stars. The amazing pressures that exist at the core of neutron stars may be like those that existed at the time of the big bang, but these states cannot be simulated on Earth.
