What is a black hole?Well mostly nothing. The Limit of Neutron DegeneracyThe upper limit on the mass of stars supported by neutron degeneracy pressure is about 3.0-3.2 MSun.If the remaining core contains more mass, neutron degeneracy pressure is insufficient to stop the collapse.In fact, nothing can stop the collapse, and the star becomes a black hole. PulsarA fast rotating, magnetized neutron star.Emits both strong radiation and high-energy particles. SNR N157B in the LMC16ms period The fastest young pulsar known pulsar
If the sun collapsed into a black hole full#
Supported by neutron degeneracy pressure.Only about 10 km in radius.A teaspoon full would contain 108 tons!Typically with very strong magnetic field Neutron starA neutron star - a giant nucleus - is formed from the collapse of a massive star, with Mcore > 1.44 Msun. For instance, Sirius is `only twice the mass of the Sun, but is 11 times more luminous, implying its life will be about 5.5 times shorter than that of the Sun:T(Sirius) ~ 2/11 T(Sun)) The more massive a Main Sequence star is, the hotter (bluer), and more luminous, the star, and the shorter its life. Thus, stars like Sirius that are about twice as massive as the Sun are about 11 times as luminous. Lifetimes of Stars On the Main Sequence, stars appear to obey a Mass-Luminosity relation: L M3.5For example, if the mass of a star is doubled, its luminosity increases by a factor 23.5 ~ 11. White Dwarf Supernova (SN-Ia)If a White Dwarf accretes enough matter from a companion star, it will eventually nova.If, after the nova, it does not shed all the mass it gained, it will continue to accrete mass until it novas again.If this process continues (accretion, nova, accretion, nova, etc.) such that the WD continues to gain mass, once it has a mass of 1.4Msun, the core will collapse, carbon fusion will occur simultaneously throughout the core, and the WD will supernova.Īnother distance indicator: White Dwarf (Type Ia) Supernovae in distant galaxies.L=4D2 lĮvolution Phases of a Star Much More Massive than the Sun (>8 Msun)Massive star, main sequence (H burning) Massive star, He burningRed giant/supergiantSupernova explosion (SN Type II)Neutron star or black holeĮxample of a Type II SupernovaThe CrabNebula:The supernova explosion that created the Crab was seen on about JAD.
![if the sun collapsed into a black hole if the sun collapsed into a black hole](https://www.extremetech.com/wp-content/uploads/2016/02/twin-black-holes-12.jpg)
Novae are nuclear explosions on the surface of white dwarf and neutron starsBrightness changes by a factor of 4000! White Dwarfs can Flare back to lifeIf they have a `younger companion When cold (~6,000-8,000 K) they may crystallize into `giant diamonds (first confirmed observationally from WD oscillations in 2004).As the heat is releases, the WD cools down and will end up a Brown, and then Black, Dwarf Most WDs have masses around 0.6 MSun The core of a WD is commonly a mixture of Carbon and Oxygen, and is releasing as light the contraction heat. WDs are prevented to collapse further by electron degeneracy (electrons, because of quantum properties, cannot be crowded more then certain limits) This fate is shared by all stars with masses below 8 MSun, and they end up with masses below 1.4 MSun.
![if the sun collapsed into a black hole if the sun collapsed into a black hole](https://assets.newatlas.com/dims4/default/161dd79/2147483647/strip/true/crop/2000x1500+0+0/resize/1280x960!/quality/90/?url=http:%2F%2Fnewatlas-brightspot.s3.amazonaws.com%2F5c%2Ff3%2F33a06567406194fe1914c4d4ad15%2Fdepositphotos-61134599-l-2015.jpg)
White DwarfsA White Dwarf is a dying star, which has terminated its nuclear fuel, and has contracted to roughly the size of the Earth.
![if the sun collapsed into a black hole if the sun collapsed into a black hole](https://media.nature.com/lw800/magazine-assets/d41586-020-02524-w/d41586-020-02524-w_18340458.jpg)
The Hertzsprung-Russell DiagramWhat will happen to the Sun, once its fuel (hydrogen) ends?Įvolution phases of a star like the SunSun today: age ~4.5 Gyrs will last another ~5 Gyr (hydrogen burning)Red giantYellow Giant (helium burning) Second red giantPlanetary nebulaĮxample of a Planetary NebulaThe HelixNebula