- "You could use the dwarf star in your exo-suit to power an entire city. But instead, you chose to become the Atom because you weren't satisfied with your small, pathetic life."
- —Eobard Thawne to Ray Palmer[src]
Dwarf star is a rare type of metal alloy that is extremely strong, dense and powerful. It can also be used to generate a blue energy in the form of blasts, shockwaves or even size alteration beams; which notably is used by the A.T.O.M. Exosuit's weapons. Dwarf star is one of the rarest, most powerful and dense metallic alloys in the entire multiverse.
Due to its density rendering the alloy extremely heavy, Superman made a key to his Fortress of Solitude from a condensed version of this alloy that only immensely strong beings can lift, as it weighs approximately 500 thousand kilograms (approximately 550 short tons).
Sylbert Rundine stole a large quantity of dwarf star alloy and was carrying it with him when he was on Central City Bus 405. The subsequent dark matter that he was exposed to reacted with the alloy and turned him into a meta-human with the power to alter the size of anything.
Mar Novu sent Oliver Queen to Earth-2 to collect dwarf star particles  and to Hong Kong on Earth-1 for Robert Wong so that a weapon could be created before the coming of the Anti-Monitor Crisis.
DC's Legends of Tomorrow
Behind the scenes
- In the real world, dwarf star is a star of relatively small size and low luminosity. Most main sequence stars are dwarf stars. The term was originally coined in 1906 when the Danish astronomer Ejnar Hertzsprung noticed that the reddest stars—classified as K and M in the Harvard scheme could be divided into two distinct groups.