Overview
- A University of Warwick paper published Thursday identifies WD J1330+6435 as the first credible green star after converting its observed spectrum into a simulated human‑vision color.
- The green hue is explained by extreme sodium absorption in the white dwarf’s ultra‑dense helium atmosphere after it accreted rocky planetary debris, while WD J1011+2845 appears deep salmon‑pink because carbon dredged from its interior forms light‑absorbing molecules.
- Researchers converted spectra from surveys and atmospheric models into human perceived colors using a standard model of human color vision to simulate how the stellar discs would look up close.
- A volume‑limited sample of about 151 white dwarfs within roughly 65 light‑years yields a median correlated color temperature near 6,800 K and shows only five objects with markedly unusual hues, implying roughly one in 30 white dwarfs are unusually colored.
- The findings are model‑based rather than direct visual observations, so individual shade assignments carry uncertainty from spectral noise, line‑broadening treatments and magnetic effects; the work links white dwarf chemistry to post‑main‑sequence planetary debris and highlights past survey biases toward hotter bluer stars.