How does a Sun-like star ultimately die?

It explodes as a supernova, leaving a neutron star behind Its outer layers are gently blown off as a planetary nebula, leaving the hot dense core as a white dwarf It collapses directly into a black hole It slowly shrinks until it is the size of a planet and becomes a brown dwarf

What is a white dwarf?

A very small, cold, dim star that has just begun fusing hydrogen A white dwarf is a young star with very little hydrogen The hot, dense, Earth-sized remnant core of a dead low- or medium-mass star, supported by electron degeneracy pressure A neutron star that has cooled down enough to become visible

How dense is a white dwarf?

Similar to the density of lead — about 11 times denser than water About the same as the Sun's core Infinitely dense — a white dwarf is actually a singularity Roughly 1 million times denser than water — a teaspoon of white dwarf material would weigh about 5.5 tonnes

What is the Chandrasekhar limit?

The minimum temperature a white dwarf can reach before it goes completely dark The maximum mass a white dwarf can have — about 1.4 solar masses — before electron degeneracy pressure fails and it collapses The maximum brightness a white dwarf can reach The age at which a white dwarf becomes a black dwarf

What supports a white dwarf against gravitational collapse?

Ongoing hydrogen fusion in a thin outer shell The rotation of the white dwarf spinning it outward Electron degeneracy pressure — a quantum mechanical force that resists electrons being packed too close together Magnetic fields generated by the white dwarf's core

What happens to a white dwarf over billions of years?

It eventually reignites and becomes a main sequence star again It collapses into a black hole once it cools below a certain temperature It gradually radiates away its heat and slowly cools over trillions of years It explodes as a nova every few thousand years as it heats and cools

What percentage of all stars in the Milky Way will eventually end their lives as white dwarfs?

About 10% — most stars become neutron stars About 50% — half go white dwarf, half go supernova About 97% — nearly all stars are not massive enough to become neutron stars or black holes Almost 0% — most stars just fade away without leaving any remnant

How fast does the gas in a planetary nebula expand outward?

About 1 kilometer per second — slower than the speed of sound in Earth's atmosphere About 20 to 30 kilometers per second About 10,000 kilometers per second — close to the speed of light About 300,000 kilometers per second — at the speed of light

Why do no black dwarfs exist in the universe today?

Black dwarfs are too small to be detected with current telescopes White dwarfs always reignite before they cool completely The cooling time for a white dwarf is longer than the current age of the universe Black dwarfs are a theoretical concept that could not form in our universe

What will happen to our Sun in about 5 billion years?

It will explode as a supernova and create a neutron star It will collapse into a black hole without exploding It will expand into a red giant, shed its outer layers as a planetary nebula, and leave a white dwarf behind It will gradually cool and shrink on the main sequence until it goes dark