University of Warwick astronomers discover the first ever green star among a rainbow of newly found white dwarf colours

Astronomers at the University of Warwick have identified WD J1330+6435 as the first star ever found that would look green to human observers, overturning earlier assumptions about the colours dying stars can display. The white dwarf's distinctive hue results from calcium, lithium and sodium in its thick atmosphere absorbing light across an unusually broad range of wavelengths. The study, published in RAS Techniques and Instruments, further establishes that white dwarfs are capable of exhibiting pink, cyan, yellow and purple tones.

Lead researcher Dr Mark Hollands said the colours 'genuinely surprised' him, as nobody had previously investigated what white dwarfs could look like up close.

White dwarfs are far denser than the outer shell of our Sun — by a factor of millions — meaning trace elements interact with the surrounding plasma and absorb light across a much wider span than they would in ordinary stars.

WD J1330+6435 has a surface temperature of around 4,000 degrees Celsius; its eerie green appearance is driven by sodium-rich rocky material the star has drawn in from its own planetary system.