If we want to understand white dwarfs then we should know that Star with 0.5 to 10 Solar Masses, loses its mass and material at high speed for thousands of years in their final moments, its outer layer create a planetary nebula and its core will shrink to earth sized body but its mass will measure in solar masses this is called White Dwarf.

There are several kinds of white dwarfs, According to an estimation, their number can reach 10 Billion in the milky way alone.

White dwarfs are core of dead stars, when they were active their core was millions of Km but gravity shrank their core to point of an earth sized body. they glow white but in very long time they will become yellow then red then Brown then Black which will become a sphere of very hot Iron or Diamond. However Black dwarfs only exists in papers and not found in universe yet.

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White dwarfs are mostly made of Degenerate Matter which forms when the stellar core’s plasma is constantly shrinking and shrinking due to gravity. On top of that Nuclear fusion is stopped so there is nothing that can prevent it from collapsing. In such hard times electrons peel away from their atoms and molecules. Just imagine an ocean which consists of electrons and in some minor way Helium and Carbon Nuclei. This is called Degenerate Matter.

Since all of its electrons have been stripped from atoms and floating in sea, this creates a repulsive force which resists the further compression.

We know that If there is more mass, Object will be bigger but here’s the opposite, massive objects become so small.
It's only one cubic centimeter consists almost 10,000 Kilograms.

That’s why White dwarfs are one of the densest objects in the universe.

In Binary systems, white dwarfs get more mass from its partner due to its immense gravity and make accretion disks which helps it eat stuffs of companion stars. Thus it can shine like normal stars.

While in some cases, white dwarfs collide with binary partners and start Type I supernovae. Where both objects explode.

If a white dwarf is single, it will lose its spin, brightness and heat. End as a black dwarf in a very long time.

These Stellar remnants are classified on the basis of elements that are 1000 times abundant than others, which lies in their thin atmosphere. Before it was thought white dwarfs are mostly dominated by Carbon and Oxygen which was made in the AGB phase.

The classification of white dwarfs initiates with the letter “D” and some other letters which are shown in the table below. White dwarf surface temperature lies between 8000 - 16000 Kelvins and core’s stays at 5 Million to 20 Million Kelvins. They can’t cool quickly because its outer layer’s opacity protects from cooling rapidly.


If we talk about their abundance in milky way. Almost 80% White dwarfs belong to DA Class, 16% are DB Type.



DQ Type has carbon dominated atmosphere and only 0.1% are DQ Type WDs.

When their surface temperature is below about 12,000 K then it will not show any important signs in spectra so it will belong to DC Class



Around 20 - 33% white dwarfs belong to metal rich White dwarfs. Metal traces are important because most in cases, any metal on white dwarf sink in the inner parts.

hint :

White - Name
White - Spectral Class
Yellow - Mass (in Solar Masses)
Orange - Temperature (in Kelvins)
Purple - Diameter (in Km)


Please Note : There is some kind of bug / issue in SpaceEngine, Most of The White dwarfs Share Same Mass and Diameter, sometimes Temperatures. I think That's a Bug Correct me If I'm wrong You can Search them in star Browser. I had Also created discussion on it But no responses. You can see this guide took more than 1 month Because I was waiting for Fixes Probably its not in Dev's To do List. If any Dev comes here by chance kindly notice this issue. it challenges accuracy of SpaceEngine.

Thank you

You know that a star can host planetary system, which may consist several planets, moons, asteroids just like our own solar system. If such Stars die they can destroy some of its nearby objects by powerful mass ejections, Expanding and swallowing etc.

Accretion disks are also slightly common feature among white dwarfs, Most of us know How Accretion disks are formed, you can check out My other guides as well so I'm not gonna discuss here but we can talk about what it does for a White dwarf its quite interesting to know.

These super hot particles rotating with ultra high speed emits powerful radiations in enormous amount, which are very dangerous. it also consist plasma of dead star and other materials such as gas and remnants of planets, dusty rocky fragments etc.

Since Star's core is now exposed which was surrounded by many layers, its gravity tries to pull everything together into accretion disk and if this matter can accumulate on white dwarf it can regain mass and sustain its life. in other words it buys more time to stay alive in universe otherwise it can totally lose rotation, heat and radiation, therefore these disks play important role for its existence.

When white dwarf start to deposit material from Disk. Sometimes, when it try to collect more material than its capacity it can eject relativistic jets due to magnetic Field instability by so doing it can't become massive like stars. However, sometimes it gets enough heat to start hydrogen shell fusion by sucking material from disk, which can lead to Nova Explosion, meaning it will explode but millions of times dimmer than Supernova and thousand times weaker than Kilonova.

We have seen accretion disks are very common among Protostars, Neutron Stars, Black Holes, Stars, Planets, AGNs or Anything with strong Gravity. Because these objects try to pull anything from enough distance and They rapidly rotate so the matter doesn't fall or collide directly with such objects instead it orbits around the source for some period, in the end they merge or collide with such central objects. however when the material orbits around them Centrifugal Force also come in existence which battles the gravity and two opposing forces are dangerously balanced. Meaning Gravity tries to pull everything into white dwarf or whatever it is while Centrifugal Force want to pull outside in the space but for thousands of years they are somehow balanced. But Gravity wins finally and swirling matter fall on White dwarf.

In addition to those two fundamental forces there is Friction along other factors which affect the Accretion disk:

When material's particles orbit they badly get rubbed together, they are obliged to follow that circular path, second things is they brutally dragged by two opposite forces. Friction among particles generate heat up to 10 Million degrees because if other materials tries to join accretion disk then the disk simply need to lose that energy.

When Friction and Gravitational force combined, it causes spirally orbit inward towards the central objects. thus they force the particles to emit their energy by brutally squeezing. it also causes turbulence in the disk.

Binary system of White Dwarfs (Actually Trinary But two are on same Side)

Scientists have found large number of Such Binary systems where one or both of them is White Dwarf. In most of the Binary systems, Their companion is in Main Sequence or later phases while some are also a white dwarf. Mostly the consume the material of its partner due to strong gravity like a Bacteria and host cells.

If a white dwarf want to stay alive itself, then it has to find source of energy. which can acquired by either residual stuff from its star phase or search another living star, by eating such materials it start recover brightness, Temperature, Rotation, Mass etc.

once they start to orbit each other, white dwarf pulls its companion Star's matter and forms an accretion disk and matter slowly deposit on white dwarf, by this way white dwarf never loses its properties and can continue itself. like predator eats their prey.

There so many possible outcomes when White dwarf is a binary member :

Possibility No. 1) As the time passes gravity bring them closer and white dwarf causes massive destruction in host star. it leads to Type Ia or Ib supernova.

Possibility No. 2) When Two low mass White dwarfs collapse together, they can Become Normal Star again. Some sort of rebirth. it can also happen if there is normal Star as its companion.

Possibility No. 3) Merger of Two Small white dwarfs can create unusual Stars like Subdwarfs Which are denoted by VI in The MK System.

Possibility No. 4) If two Large White dwarfs Collide together, it can make Neutron Star.

Possibility No. 5) When they are massive enough, they will create again White dwarf but larger than their binary partners. White dwarf known as WDJ0551+4135 which was result of two merging white dwarfs, it was massive than typical White dwarf and had abundant Carbon in atmosphere.

Possibility No. 6) sometimes, The collision of two Large WD's can trigger Type Ia supernova and this time they both kill each other. Such supernova will outshine its entire galaxy and easily seen from millions of Light years. its light used as an instrument that measures cosmic distances.

Possibility No. 7) If WD gets none of the above, Then it will lose is Shine, Spin and Mass, will become Black dwarf which would made of Coal or Diamond. However, Whether WD is Single or Binary They always Getting little amount of mass by Pulling matters through Gravity, But that's Not enough for their survival.

According to a study in 2020, About 10 to 30 % WD's are result of Binary WD collisions.

In this Guide we discussed in white dwarfs, Sorry for Making this guide too late I think It took around 2 month. Actually I was Waiting If there any fixes will come behalf developer team, I got no choice I had to Upload it.

Anyway Thanks for Reaching and Reading this guide.

We'll meet in another interesting guide.

Have an awesome Day