White Dwarf WD J1330+6435 Shines Green 280 Light-Years From Earth
Astronomers have identified the first known green star, an ultra-dense stellar remnant located 280 light-years away in the constellation Draco. The object, cataloged as WD J1330+6435, is a white dwarf—the exhausted core of a dead star that has shed its outer layers, a fate that will eventually await our Sun.
While normal stars shine in shades of blue, white, orange, or red, this remnant emits a striking yellow-green hue due to planetary debris falling into its atmosphere. Mark Hollands, an astrophysicist at the University of Warwick and lead author of the study published in RAS Techniques and Instruments, explained that planetary fragments once orbiting the star crashed onto its surface, polluting the stellar atmosphere with heavy elements including calcium, lithium, and sodium.
"It turns out that scientists have discovered that our star may indeed go green, but only billions of years from now after its death — and only if it then starts eating planets like a cosmic zombie." via @SPACEdotcom https://t.co/GtaqMsmJRH pic.twitter.com/wS0Ilh5nra
How Sodium and Calcium Shift the Stellar Spectrum
The unusual color stems from specific atomic interactions in the white dwarf’s dense outer layers, where temperatures hover around 4,000 degrees Celsius. Under normal conditions, sodium absorbs a narrow band of orange light. In the high-pressure atmosphere of WD J1330+6435, sodium atoms collide constantly with helium atoms, causing the element to absorb a much wider swath of the light spectrum.
This expanded absorption blankets yellow, orange, and portions of red light. Simultaneously, calcium absorbs the violet portion of the spectrum, leaving behind a haunting green glow tinged with yellow. “Imagine standing on a planet and looking up at a green star,” Hollands said in a university press release. “It feels like a scene from sci-fi.”
Why Human Eyes Cannot See the Green Glow Directly
Directly spotting a green star through a telescope remains impossible because white dwarfs are exceptionally small and distant, leaving their true visible colors obscured. Instead, researchers at the University of Warwick analyzed the light emitted by these objects by breaking it down into individual wavelengths and creating computational models of stellar spectra.
By applying computer models of human vision to the spectroscopic data, the team calculated what color an observer would perceive if they could travel close enough to view the white dwarfs directly. The analysis revealed that stellar remnants can produce unexpected tones far outside standard astronomical classifications.
Carbon Molecules Create Salmon-Pink White Dwarfs
The survey of white dwarfs also uncovered other extreme atmospheric anomalies, including a candidate for one of the reddest known stars. Located 48 light-years from Earth, the white dwarf designated WD J1011+2845 emits light heavily distorted by carbon molecules in its atmosphere, producing a deep salmon-pink glow.
Boris Gänsicke, an astrophysicist at the University of Warwick who participated in the research, compared the phenomenon to mixing paints on an artist’s palette. “If you remove one of the colors from that mixture, the resulting shade changes,” Gänsicke told Reuters, noting that carbon enrichment shifts certain stars into pink and violet hues, while others shine in pale blue or turquoise.
Survey Results Reveal How Rare Colorful White Dwarfs Are
Despite these striking exceptions, colorful white dwarfs remain rare anomalies across the local stellar neighborhood. Out of 151 white dwarfs examined within a 65-light-year radius of Earth, researchers found only five with unusual color profiles—two appearing yellow and three displaying pink shades.
This ratio indicates that roughly one out of every thirty white dwarfs shines with an atypical color driven by atmospheric pollution from consumed asteroids and planetary fragments. The findings expand our understanding of how planetary systems impact the final evolutionary stages of stars.
Frequently Asked Questions About White Dwarf WD J1330+6435
Can humans ever travel to see WD J1330+6435 in person?
No human spacecraft can travel to WD J1330+6435, which sits 280 light-years away in the constellation Draco. Researchers rely entirely on spectroscopic analysis and computer models to determine its hypothetical visual color.
What temperature does the green white dwarf reach?
The surface temperature of white dwarf WD J1330+6435 is approximately 4,000 degrees Celsius, representing the cooling remnant of a Sun-like star that has exhausted its nuclear fuel.
How many unusual white dwarfs did the Warwick team discover?
Researchers analyzed 151 white dwarfs within 65 light-years of Earth and identified five objects with abnormal coloration, including two yellow stars and three pink stars.