A green star?
Read the light.
The green-star discovery concerns a white dwarf whose light could look green to a nearby observer. Researchers inferred the perceived color from spectra and atmospheric models; the result is not a close-up telescope photograph of a green stellar surface.
Sources checked October 17, 2026 — the research paper, the University of Warwick release and NASA’s stellar-evolution background. This is a source-based explainer, not our own astronomical observation.
The key object: WD J1330+6435. The study links its unusual color to strong absorption by sodium in a dense white-dwarf atmosphere.
First, what is a white dwarf?
A white dwarf is the compact remnant left after a star has shed its outer layers. It can remain hot and luminous while cooling. NASA’s explanation of stellar evolution describes how a medium-sized star leaves this remnant after its red-giant stage.
How do you measure a color from far away?
A spectrum records how much light arrives at different wavelengths. The researchers combined spectra with the response of human color vision to calculate how that light would appear. Their research paper also uses atmospheric models to render stellar discs as they could look from close enough to resolve them.
A rendered disc illustrates a calculated color. It is not a photograph taken next to the star, and its brightness is reduced for display.
| What you are reading | What it establishes |
|---|---|
| A measured spectrum | The distribution of received light by wavelength. |
| A calculated perceived color | How a human visual response combines that spectrum. |
| A rendered stellar disc | A visualization based on a model, rather than a resolved surface photograph. |
Why can this one look green?
For many stars, temperature is the main guide to their apparent color. The extreme density of some white-dwarf atmospheres makes chemical composition much more important: absorption features can spread across broad parts of the visible spectrum.
In its October 15 explanation, Warwick identifies sodium-rich material in WD J1330+6435. Broad sodium absorption removes much of its yellow, orange and red light, shifting the balance of the remaining light toward green. Other atmospheric mixtures can produce pink, purple or cyan appearances.
Are white dwarfs usually green?
No. The study also examines a local sample extending to 20 parsecs, about 65 light-years. Most of those white dwarfs have much more ordinary colors. The paper reports a median correlated color temperature close to 6,800 K for the objects near the usual thermal-color sequence.
The nearby sample describes typical colors; the individual green example demonstrates an unusual atmospheric effect. Green is not the normal white-dwarf appearance.
Read the original result
Read Any colour you like: the diverse chromaticities of white dwarfs, by Mark A. Hollands and colleagues, for the spectra and calculations.