Study Reveals White Dwarf Stars May Appear Green and Pink, Challenging Popular Images of Stellar Remnants
Astronomers have uncovered a surprising feature of white dwarf stars, revealing that these stellar remnants can appear in unusual colours, including green, pink, purple, yellow and cyan. The findings challenge the popular image of white dwarfs as uniformly white or pale-blue objects and highlight how the extreme conditions inside their atmospheres can influence the light they emit.
The research, conducted by astronomers at the University of Warwick, shows that a star’s visible colour depends not only on its temperature but also on its atmospheric chemistry. Published in the journal RAS Techniques and Instruments in October 2026, the study offers a fresh perspective on how scientists understand and interpret the appearance of stellar remnants.
White dwarfs form when stars similar to our Sun exhaust their nuclear fuel and shed their outer layers, leaving behind a compact, extremely dense core. These remnants gradually cool over billions of years. Despite their small size, they preserve valuable information about the final stages of stellar evolution and the history of planetary systems that once orbited their parent stars.
One of the most striking examples identified by researchers is WD J1330+6435, a white dwarf located approximately 284 light-years from Earth. According to the study, calculations of its spectrum suggest that it would appear greenish, with a chartreuse-like hue, if it could be observed up close.
The unusual colour is linked to rocky material from the star’s former planetary system that has accumulated in its atmosphere. Elements including sodium, calcium and lithium alter the wavelengths of light escaping from the star. Under the extreme atmospheric conditions of a white dwarf, these elements absorb light across broader wavelength ranges, producing a colour that differs significantly from what temperature alone would predict.
The researchers also identified white dwarfs that could appear pink or purple because of carbon-rich atmospheres. One example, WD J1011+2845, lies approximately 48 light-years away and may display an intense salmon-pink colour. Scientists believe that convection can transport carbon from deeper inside the star towards its surface, where carbon molecules absorb substantial portions of visible light and change the resulting colour.
Other white dwarfs may appear yellow, cyan or pale blue, depending on their atmospheric composition and temperature. Stars that accumulate debris from shattered asteroids and comets can develop unusual yellowish tones, while certain cool white dwarfs with mixed hydrogen and helium atmospheres can appear cyan because of the way these gases interact under extreme conditions.
To determine these colours, the research team analysed stellar spectra, which record the intensity of light at different wavelengths. The scientists then applied models of human colour vision to estimate how the stars would appear to the naked eye if their surfaces could be resolved clearly from a nearby vantage point.
This distinction is important because the colours described in the study are calculated from scientific observations and models rather than directly seen by human observers standing close to the stars. White dwarfs are so distant and compact that they generally appear as points of light even through powerful telescopes. Their atmospheric chemistry, however, can be investigated through the light they emit.
The team also examined a representative sample of 151 white dwarfs located within approximately 65 light-years of Earth. Five showed particularly unusual colours: two appeared yellow and three pink. The researchers estimated that roughly one in 30 white dwarfs across the wider population could display an unusually coloured appearance.
Despite these discoveries, the study does not suggest that most white dwarfs are green or pink. The sample’s median colour temperature was approximately 6,800 kelvin, consistent with white light. The findings instead demonstrate that a minority of these stellar remnants can depart substantially from the colours traditionally associated with stars.
The research also challenges the assumption that white dwarfs are generally blue. Hotter white dwarfs tend to be brighter and easier to detect across greater distances, meaning they are disproportionately represented in surveys that select objects according to brightness. A more representative sample provides a clearer picture of the population as a whole.
Beyond their unusual appearance, these colours could help astronomers investigate the composition of stellar atmospheres, the processes that transport material within aging stars and the remnants of planetary systems. Elements detected in a white dwarf’s atmosphere can provide clues about asteroids, comets and other rocky bodies that survived until their host star entered its final evolutionary stages.
The discovery illustrates how familiar astronomical objects can reveal unexpected characteristics when scientists examine them in greater detail. White dwarfs remain important laboratories for studying stellar evolution, and their varied colours offer another way to explore the complex physical and chemical processes occurring in the final stages of a star’s life.
