Astronomers have uncovered evidence of an extraordinary planet that may have formed from the ashes of a dead star. Researchers at the University of Warwick used observations from NASA’s Hubble Space Telescope to make the discovery, which centers on a white dwarf star— the dense remains of a dead star. Scientists believe a rare second-generation planet could orbit it, a world formed from material expelled during its parent star’s death.

The findings, published in Nature Astronomy this month, could change scientists’ understanding of what happens to planets after their stars reach the end of their lives.

Hubble Uncovers A 27-Year-Old Mystery

The breakthrough came after astronomers revisited Hubble observations from 1999. Those original measurements contained approximately 100 unidentified chemical features that had remained unexplained for more than two decades.

Using an updated database of chemical signatures, lead researcher Jamie Williams, a doctoral candidate at the University of Warwick, discovered that many of the mysterious features matched niobium, a heavy element never previously identified in a white dwarf star’s atmosphere. “What Hubble is showing us in this white dwarf system is something we haven’t seen before: a high abundance of the element niobium,” said Williams.

How Could A Planet Form From A Dead Star?

White dwarfs are the dense, collapsed remnants of stars that have exhausted their nuclear fuel and shed their outer layers. Although planets can survive this transformation, researchers believe the suspected world around this particularly dark star — called HS 0209+0832—may have formed afterward.

Unlike Earth and the other planets in our solar system, which developed from material surrounding the young sun, second-generation planets are thought to emerge from matter released as a star dies.

The unusual chemical composition provides an important clue. Elements such as niobium are astronomically special because only dying stars form them — and eject them as they shed their outer layers. Researchers suspect that some of this expelled matter accumulated into a disc, potentially with help from a companion star, before eventually forming a Jupiter-sized gas giant.

“Second-generation planets are worlds that form out of the material a star casts off as it dies,” said Williams. “They’re incredibly rare, and finding one around a white dwarf was completely unexpected. It’s a bit like finding a planet that has risen from the ashes of the very star it once orbited.”

NASA’s TESS Satellite Detects Signs Of A Giant Planet

More evidence came from NASA’s Transiting Exoplanet Survey Satellite — launched in 2018 to hunt for planets orbiting bright stars in the Milky Way — which monitored the white dwarf for four months and detected regular variations in its brightness.

The signal repeats approximately every 4.4 days, suggesting a possible planet orbiting about 3.7 million miles from the star. That’s much closer than Mercury is to the sun. Scientists think the candidate planet could be about the size of Jupiter. However, its proximity to the extremely hot white dwarf means intense radiation may be stripping its atmosphere.

That escaping gas could form a comet-like tail, eventually creating a disc around the star before falling onto its surface. This process would explain why Hubble detected such unusual concentrations of heavy elements in the white dwarf’s atmosphere.

Could The Planet Eventually Become Habitable?

Despite the extreme conditions, researchers believe the suspected planet could survive for an extraordinarily long time. As the white dwarf gradually cools, the intense radiation stripping the planet’s atmosphere should weaken, potentially allowing the world to remain in a more stable environment.

“If the second-generation planet is there, I think it is likely to survive,” said Williams. “Eventually the white dwarf will cool and then maintain a consistent temperature, with the planet in its stable habitable zone for millions of years.”

If confirmed, it’s the first compelling example of a second-generation planet orbiting a white dwarf, opening an entirely new avenue of research into planetary formation. A search for more white dwarfs with similar chemical signatures will reveal whether second-generation planets are rare or just hard to find.

Wishing you clear skies and wide eyes.