Brief
Astronomers identify first green‑coloured white dwarf star
A team led by Mark Hollands used spectral data to model the colour of a white dwarf that appears green, the first such star identified.
By Felo News Desk · Published
A study published on 16 October 2026 reports the discovery of the first green‑coloured white dwarf, designated WD J1330+6435, after researchers modelled its spectrum and simulated how it would look to the human eye.
What happened
The team analysed the spectral fingerprint of WD J1330+6435, a white dwarf with a surface temperature of about 4,000 °C. By feeding the data into a model that accounts for atmospheric composition, they found that the star’s atmosphere contains calcium, lithium and, crucially, sodium. The sodium absorbs orange wavelengths, leaving a chartreuse‑green glow.
What the reports add
The Independent notes that white dwarfs were previously thought to be “perfect radiators” whose colour depends solely on temperature, ranging from orange (cool) to blue (hot). The new research shows that the chemical makeup of a white dwarf’s atmosphere can dominate its colour, producing hues such as pink, cyan, yellow, purple and, in this case, green.
What was said
"Most stars, including most white dwarfs, behave like ‘perfect radiators,’ so their colour is set almost entirely by temperature. But nobody had really looked into what else might be possible for white dwarfs," said Mark Hollands of the University of Warwick, who led the work.
"The traces of sodium in the atmosphere of this white dwarf absorb the orange part of the spectrum, leaving behind a ghostly green glow," Hollands added.
How it came about
Because no white dwarf is close enough for direct visual observation, the researchers relied on spectral data from telescopes and applied a model that translates the spectrum into perceived colour. Their analysis builds on earlier findings that white dwarfs can accrete material from surrounding planetary debris, altering their atmospheric composition.
Key facts
- WD J1330+6435 is a white dwarf with a surface temperature of about 4,000 °C. (independent.co.uk)
- The star’s atmosphere contains calcium, lithium and sodium, giving it a chartreuse green colour. (independent.co.uk)
- Researchers used spectral data and a colour‑simulation model to calculate the star’s visual appearance. (independent.co.uk)
- The discovery challenges the view that white dwarf colour is determined solely by temperature. (independent.co.uk)
Sources
- [1] independent.co.uk — originally reported as “Astronomers have just found the first green star. Here’s why it matters”
