Astronomers have found a young star, TOI 1227, that's blasting a planet in orbit around it with intense X-rays, causing it to tear apart.
NASA’s Chandra X-ray Observatory is giving scientists a view of this destructive process in real time, providing a front-row view of the chaotic early life of planetary systems.
Planet melting under pressure
Life's not easy for a baby planet.
TOI 1227 b is about about 8 million years old, which means it's a mere infant. For comparison, Earth is about 4.5 billion years old.
About the size of Jupiter, TOI 1227 b orbits a small host star at a scorchingly close distance, even tighter than Mercury’s orbit around our Sun.
But this close relationship comes at a cost. Star TOI 1227 is unleashing a relentless barrage of X-rays, and planet TOI 1227 b is taking the full hit.
These powerful rays are stripping away the planet’s thick, gassy atmosphere, then trailing off in a dramatic tail, a bit like a comet.
Astronomers say TOI 1227 b could eventually be transformed from a bloated gas giant into a small, rocky husk.
How fast is TOI 1227 b disappearing?
Using Chandra's sensitive instruments, researchers measured how many X-rays the star is emitting, and the effect this barrage is having on the orbiting planet.
Computer models enabled them to work out how much atmosphere the planet is losing.
It's losing the equivalent of Earth's atmosphere every 200 years. In just a few million years, TOI 1227 b could shrink dramatically.
How we know this planet is an infant
How is it possible to accurately calculate the age of a planet, and know that TOI 1227 b is so young?
Astronomers used two methods. The first relied on measurements of how TOI 1227 b’s host star moves through space, relative to other populations of nearby stars with known ages.
The second method compared TOI 1227 b's brightness and surface temperature with theoretical models of evolving stars.
Together, these methods told the astronomers that the planet is just 8 million years old.
That makes TOI 1227 b the second youngest planet ever seen passing in front of its host star (an exoplanet-study method known as the transit method).
This is a snapshot of planetary adolescence, captured in action.
A key insight into young planet systems
Among all the known exoplanets younger than 50 million years, TOI 1227 b has the longest orbit and orbits the lowest-mass host star.
Along with the fact it's getting fried by X-rays from the star, astronomers see this as a perfect candidate for future observations.
And by watching what happens to the planet, scientists hope to learn how worlds like Earth might have looked in their earliest, most volatile days – and what shapes their destinies in the end.
Read the full paper at ui.adsabs.harvard.edu/abs/2025arXiv250604440V/abstract
