A dead star's double ring of planet debris hints at how our solar system could end

Astronomers have found a dead star circled by two separate rings of shattered planet debris, a possible preview of our own solar system's far future, the European Southern Observatory said Oct. 27.

What is a dead star?

The star, a white dwarf called J1328−1450, is the dense, burnt-out core left behind when a star like the sun runs out of fuel.  White dwarfs pack roughly the mass of the sun into a ball about the size of Earth, NASA material explains.  This one holds about half the sun's mass, the study found.

It lies about 1,600 light-years from Earth, the University of Warwick said.  A light-year is the distance light travels in a year, so the light seen now left the star about 1,600 years ago.

Out of fuel, but still hot

The team measured the star's surface at about 17,400 kelvins, roughly 31,000 degrees Fahrenheit, about three times hotter than the sun's surface.

How can a star with no fuel be that hot?  "Out of fuel" means its core no longer fuses atoms together, the nuclear reaction that powers living stars.  What remains is leftover heat, the way a stove burner glows after it is switched off.  A new white dwarf is hotter than 100,000 kelvins and then cools over a billion years or so, NASA material explains.  This one has already cooled a long way.

Once a giant

An Earth-sized star could not swallow planets, and it didn't.  It was far bigger then.  Near the end of its life, a star like the sun swells into a red giant, NASA material explains, and engulfs planets orbiting close in.  It then sheds its puffed-up outer layers into space, leaving only its small, hot core:  the white dwarf.  So yes, it swelled, then lost its outer layers.

How big does it get?  A red giant can be some 100 times wider than the sun, says an illustration caption on NASA's website.  A 2008 study of the sun's future in Monthly Notices of the Royal Astronomical Society, by Klaus-Peter Schröder and Robert C. Smith, puts the sun's peak at about 256 times its current width, reaching past Earth's orbit.  NASA says the sun will engulf Mercury and Venus, and possibly Earth.

Rocky bodies farther out can survive.  Some later break apart and form a disc of debris around the remnant, the University of Warwick said.  The closer a body comes, the more easily the white dwarf's gravity tears it apart.

Two rings, two survivors

Other dead stars have one ring of debris.  This one has two, with a clear gap between them.  The team, writing in Nature Astronomy, thinks two surviving bodies keep the rings apart:  an asteroid a few kilometers wide and an outer one possibly as large as Pluto or even our moon.

this is the first example of a complex system with a double debris disc

How they know what the debris is made of

The rings are far too small and distant to photograph.  Instead, the team used the X-shooter instrument on ESO's Very Large Telescope in Chile to spread the star's light into a spectrum, a rainbow of colors.  Each chemical element gives off light only at its own set of colors, like a fingerprint, so bright lines at those colors reveal which elements are in the hot gas around the star.

Those fingerprints showed calcium, oxygen, magnesium and iron, a mix like the rocky planets of our solar system.  The inner ring is rich in magnesium; the outer ring has little.  That suggests the debris came from two different planets, or from different layers of one, such as its crust and core, ESO said.

The same lines also reveal the rings' shape.  Gas moving toward us looks slightly bluer and gas moving away slightly redder.  A single spinning ring makes each line split into two peaks; this star showed four, meaning gas circling at two different speeds, the paper reports.  The inner ring lies about 100,000 to 240,000 kilometers from the star, the outer about 375,000 kilometers to more than 1.3 million.

We cannot see the two planetary bodies directly, but we can infer their likely presence from the shape and composition of the gas.

The sun will one day become a white dwarf too, in about 5 billion years, NASA says.

Source:  European Southern Observatory release eso2613, Oct. 27, 2026; University of Warwick release, Oct. 27, 2026; Nature Astronomy (doi:10.1038/s41550-026-03004-3); NASA Science, "Hubble's Nebulae," "Sun: Facts" and "The life cycle of a Sun-like star (annotated)"; NASA Imagine the Universe, "White Dwarf Stars" (NASA material, summarized by AI for the Daily News; NASA did not review this story); Schröder and Smith, Monthly Notices of the Royal Astronomical Society, 2008 (doi:10.1111/j.1365-2966.2008.13022.x).  This story was drafted by AI from ESO material, and the ESO text was modified by AI.