In brightest day, in blackest night, there is now a real green star. Astronomers at the University of Warwick have identified the first known star that would glow green to human eyes, and it is hard not to think of the Green Lantern Corps and the emerald light that powers every ring in the DC Universe.
The star is a white dwarf named WD J1330+6435. A new study led by Dr. Mark Hollands, published last week in RAS Techniques and Instruments, found that it would shine a ghostly chartreuse green if you could see it up close. Even Hollands reached for a sci-fi comparison when describing it.
"Imagine standing on a planet and looking up at a green star. It feels like something out of science fiction," he said.
The Science Behind The Green Light
Green Lantern's power comes from willpower channeled through the Central Power Battery on Oa. This star's green glow has a far more grounded explanation. White dwarfs are the dense cores left behind after Sun-like stars die, and the coolest ones have atmospheres about as dense as water.
WD J1330+6435 is around 4,000 degrees Celsius and has swallowed rocky debris from its own planetary system, loading its atmosphere with calcium, lithium, and sodium. Under that crushing density, the sodium absorbs the orange part of the star's light while calcium absorbs the violet, so what is left peaks in the green part of the spectrum.
"The traces of sodium in the atmosphere of this white dwarf absorb the orange part of the spectrum, leaving behind a ghostly green glow," Hollands explained.
Normal stars only come in orange, white, or blue, with temperature deciding which. According to the research team, no star of any kind has ever been credibly reported as green before, making this the first known genuinely green star in the galaxy.
A Villain-Worthy Origin Story
The darker detail would fit right into a cosmic comic. The green color exists because the white dwarf has been tearing apart what is left of its planets. In an interview with CNN, Hollands described how asteroids and other rocky material that venture too close get shredded into dust, which then falls onto the star and mixes into its outer layers. That lets astronomers study the chemistry of those destroyed worlds.
A star that glows green because it feeds on planets sounds like something the Guardians of the Universe would warn their recruits about. It is also a reminder that real space can be every bit as strange as the stuff on the comic page.
The study found other colorful white dwarfs too, including pink and purple stars rich in carbon, cyan ones with mixed hydrogen and helium atmospheres, and a salmon-pink star called WD J1011+2845 that may be the reddest ever recorded. Across the 151 white dwarfs within about 65 light years of Earth, the team found that roughly one in thirty has an unusual color, while the average white dwarf is simply white.
Green Lantern Is Having A Moment
The timing works out nicely for DC fans. Lanterns, the DC Studios series starring Kyle Chandler as Hal Jordan and Aaron Pierre as John Stewart, wrapped its eight-episode first season on HBO earlier this month, and every episode is now streaming on HBO Max. The show was created by Chris Mundy, Damon Lindelof, and Tom King.
A second season has not been ordered yet. In an interview with Collider, DC Studios co-chief Peter Safran said fans should hear about the show's future before the end of the year, and praised the series for bringing Green Lantern back into the conversation.
As for real green stars, Hollands told CNN that new spectroscopic surveys could help astronomers go from one or two green white dwarfs to as many as 10 or 20. The Corps may have more sectors to patrol than we thought.
What other fictional series does the green star remind you of? Sound off with your thoughts in the comments below.