ScienceAlertScientists Reveal a Chilling Glimpse of The Sun's Future DeathIvan Farkas
Sun, November 9, 2025 at 8:07 PM EST
4 min read
In this illustration, an asteroid (at bottom left) breaks apart under the powerful gravity of a bright sphere at the center of an orange disk ,representing LSPM J0207+3331, the oldest, coldest white dwarf known to be surrounded by a ring of dusty debris. Scientists think the system’s infrared signal is best explained by two distinct rings composed of dust supplied by crumbling asteroids.What's the best way to reveal what an exoplanet is made of? Wait for it to get gravitationally shredded and engulfed by its star, of course!
Astronomers using the W. M. Keck Observatory on Mauna Kea, Hawaiʻi, have spotted such a gruesome glimpse of stellar cannibalism: a dead Sun-like star gobbling up the remains of its shattered planet – more than 3 billion years after said star became a white dwarf.
This delayed destruction is more than surprising; it "challenges our understanding of planetary system evolution," says astrophysicist Érika Le Bourdais of the University of Montreal in Canada, the paper's first author.
This discovery also offers a chilling look at what may occur in our own Solar System, more than 5 billion years in the future after our Sun expels its outer layers into space and becomes a cooling cosmic cinder, or white dwarf.
Most importantly, researchers detected the presence of 13 heavy elements within the white dwarf's photosphere. That's the highest number yet reported for a hydrogen-rich white dwarf, revealing the shredded remains of an ancient planet that was at least 200 kilometers (120 miles) wide and had a rocky mantle and metallic core – analogous to Earth.
The white dwarf in question is called LSPM J0207+3331 and is located 145 light-years away from Earth in the constellation Triangulum.
Artist's impression of a white dwarf gobbling up the remnants of its planetary system. (NASA, ESA, Joseph Olmsted/STScI)Detecting so many heavy elements is unexpected in a cool, hydrogen-rich white dwarf, as Le Bourdais explains: "Their atmospheres are more opaque, and heavy elements sink quickly toward the star's center. We expected to see only a few elements."
In contrast, these elements are easier to identify in warmer, helium-rich white dwarfs because helium is more transparent and the elements take longer to sink through the atmosphere, on the order of millions of years, compared to just a few days for a colder, hydrogen-dominated dwarf.
Yet hydrogen-rich white dwarfs are aplenty, representing the overwhelming majority of dead Sun-like stars. They're also some of the oldest stars in the Milky Way. Therefore, this study presents a new way of analyzing long-term planetary evolution of ancient bodies around (dead) stars similar to our own.
Because, in possibly ironic fashion, these white dwarfs can uniquely reveal the composition of exoplanets by destroying them. Planetary details like chemical composition and rocky cores are inaccessible to direct observations. But when a planet is gobbled up by its white dwarf, its elements leave telltale chemical fingerprints in that dwarf's previously pristine hydrogen atmosphere.
As a result, researchers have ascertained that the destroyed planet has a high core mass fraction of approximately 55 percent. This measurement shows that a planet's core constitutes a significant portion of its total mass. For perspective, Mercury's abnormally high core mass fraction is about 70 percent, while Earth's is around 32 percent.
This study also showcases the eternal variability of planetary systems.
"Something clearly disturbed this system long after the star's death," says John Debes, astronomer at the Space Telescope Science Institute in Baltimore and study co-author.
The exact mechanics are still mysterious. As stars age, die, and lose mass, they can destabilize the orbits of the planets and other bodies around them. Alternatively, the torn-apart planet may have been disturbed by the orbital influence of the other planets in the system. This delayed instability "could point to long-term dynamical processes we don't yet fully understand," adds Debes.
Going forward, scientists hope to find additional clues to identify whether the planetary destruction occurred due to the influence of Jupiter-sized planets, which can nudge smaller planets on a path to disaster. However, these potential alien Jupiters would be difficult to detect due to their low temperatures and distance from the dwarf.
Still, their presence may be gleaned using archival data from the European Space Agency's now-retired Gaia space telescope. Along with infrared readings from NASA's James Webb Space Telescope, such additional data points could pinpoint the culprit (or culprits) of this cosmic crime scene 3 billion years in the making, and unveil the secrets of multi-planet evolution in other "dead" systems across the universe.
Finally, analyzing the make-up of other worlds destroyed by white dwarfs will allow astronomers to test "exoplanet formation and evolution on a galactic scale" to uncover the secrets of how alien worlds (including Earth-like planets) form, grow, and die.
This research is
published in The Astrophysical Journal.
https://www.yahoo.com/news/articles/dead-stars-last-meal-reveals-010720559.html
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