New research suggests that aging stars may be destroying the giant planets orbiting nearest to them—a dramatic process that could foreshadow the distant future of our own solar system.
The study, led by astronomers from University College London (UCL) and the University of Warwick, provides some of the clearest evidence yet that stars can pull their close planets inward and ultimately consume them as they grow old.
When stars like the Sun exhaust the hydrogen fuel at their cores, they begin to cool, expand, and transform into red giants—massive, swollen versions of their former selves.
For the Sun, this transformation will take place in about five billion years.
As the star expands, its gravity and magnetic fields interact more strongly with the planets orbiting nearby, setting off a slow but unstoppable chain of events that can lead to planetary destruction.
In the new study, published in Monthly Notices of the Royal Astronomical Society, the researchers examined nearly half a million stars that had just entered this so-called “post-main sequence” stage of their lives.
Using data from NASA’s Transiting Exoplanet Survey Satellite (TESS), they searched for the telltale dips in starlight that occur when planets pass in front of their stars.
After analyzing more than 15,000 signals and filtering out false positives, the team identified 130 planets and planet candidates, including 33 newly discovered ones.
The results revealed a striking pattern: giant planets close to their host stars were far less common around stars that had already expanded into red giants.
According to lead author Dr. Edward Bryant of UCL and the University of Warwick, this finding is “strong evidence that as stars evolve off their main sequence, they can quickly cause planets to spiral into them and be destroyed.”
The likely culprit is a phenomenon called tidal interaction—a gravitational tug-of-war between a star and its planet. “Just like the Moon pulls on Earth’s oceans to create tides, a planet pulls on its star,” Bryant explained.
“As the star expands, this interaction grows stronger, slowing the planet down and causing it to spiral inward until it breaks apart or falls into the star.”
The researchers found that the likelihood of a star hosting a close-in giant planet drops sharply as it ages—from about 0.35% in younger stars to just 0.11% in red giants.
Co-author Dr. Vincent Van Eylen noted that the findings also offer a glimpse into our Sun’s distant future. “When the Sun becomes a red giant, it could engulf some of the inner planets,” he said. “Earth is probably safe—but life on Earth would not be.”
The team’s next step will be to measure the masses of these planets precisely to confirm their identities and better understand how—and how fast—aging stars consume their worlds.
Source: University College London.
