Green, pink and purple: Astronomers reveal the surprising true colors of white dwarf stars

Key Points:

• University of Warwick astronomers discovered that white dwarf stars can emit a variety of colors beyond the typical orange, white, and blue, including green, pink, cyan, yellow, and purple, due to the dense atmospheres affecting light absorption.
• The study identified the first known genuinely green star, WD J1330+6435, whose atmosphere enriched with calcium, lithium, and sodium absorbs orange light, producing a unique chartreuse green glow.
• Another notable finding is WD J1011+2845, potentially the reddest star recorded, exhibiting a deep salmon-pink color caused by carbon molecules distorting its light spectrum.
• Analysis of 151 nearby white dwarfs revealed that about one in 30 display unusual colors, while the majority maintain a median color temperature around 6,800 K, perceived as white, correcting the misconception that white dwarfs are typically blue.
• These findings highlight how the dense atmospheres and chemical compositions of white dwarfs influence their color, expanding our understanding of stellar appearances beyond temperature-based expectations.