Green star WD J1330+6435: Why it is called a ‘zombie’

Astronomers have identified an unusual white dwarf, WD J1330+6435, about 326 light-years from Earth, whose atmosphere could give it a chartreuse-green glow. The Economic Times reported on October 18, citing international science coverage, that researchers link the colour to sodium deposited as the stellar remnant draws in rocky planetary material.

The findings were published in RAS Techniques and Instruments in October 2026. The team’s modelling suggests that the combination of atmospheric composition and extreme density produces the unusual hue. Researchers describe the object as potentially the first credibly reported genuinely green star; that priority claim and the modelled colour should be distinguished from an independently confirmed visual observation.

What makes this white dwarf look green?

The research was led by Mark Hollands, an astrophysicist at the University of Warwick in England. According to the account, the team became interested in WD J1330+6435 because infalling planetary material had enriched its outer layers with calcium, lithium and, especially, sodium.

Sodium ordinarily absorbs light in a narrow orange portion of the spectrum. In this white dwarf’s exceptionally dense atmosphere, however, surrounding helium atoms repeatedly collide with sodium atoms, changing their atomic energy levels.

Hollands explained that this broadens the range of light sodium absorbs to include yellows, oranges and some reds. Removing more of those warmer wavelengths changes the balance of the escaping light, producing the chartreuse-green appearance predicted by the team’s model. The explanation therefore depends on both the presence of sodium and the unusual physical conditions around it—not simply on a star containing a particular element.

Why the ‘zombie star’ nickname?

A white dwarf is the dense remnant left when a star such as the Sun exhausts its nuclear fuel. WD J1330+6435 has been accreting, or drawing in, rocky material from its planetary surroundings, adding elements to its atmosphere after the original star’s active lifetime.

That combination of a stellar remnant and continued consumption of nearby material gives the object its ‘zombie’ nickname. It is a descriptive label, not evidence that the star has returned to its earlier fuel-burning state.

Could the Sun eventually turn green?

The Sun is expected to become a white dwarf billions of years from now, but that does not mean it will acquire the same colour. Its eventual appearance would depend on its atmospheric composition and physical conditions.

The reported finding suggests that some stellar remnants may display a wider range of colours than astronomers have traditionally expected. It also links a remnant’s appearance to the fate of material in the planetary system that survives around it.