Stellar cores called white dwarfs come in an astonishing array of colors, including what scientists say is the first known green star and the reddest star ever found, new research reveals.

A white dwarf star is the dense, cooling core that remains after a low- to medium-mass star runs out of fuel. The new study, published Thursday (Oct. 15) in the journal RAS Techniques and Instruments, shows that white dwarfs come in far more colors than their name suggests.