Young Exoplanet TOI 1227 b Loses Atmosphere Under Stellar Assault

NASA’s Chandra X-ray Observatory, in collaboration with the Hubble Space Telescope, has identified a young exoplanet, known as TOI 1227 b, that is rapidly losing its atmosphere due to intense stellar radiation. Located approximately 8 million years from formation, this Jupiter-sized planet orbits a faint red dwarf star and is undergoing significant atmospheric erosion.

The powerful X-ray emissions from the star are stripping away TOI 1227 b’s thick gas envelope at an alarming rate. Research indicates that this planet is losing an amount of gas equivalent to Earth’s entire atmosphere roughly every 200 years. According to scientists, the planet’s atmosphere “simply cannot withstand the high X-ray dose it’s receiving,” leading to rapid changes in its structure.

Insights from Observational Data

The study utilized data from the Chandra X-ray Observatory alongside earlier observations from the Hubble Space Telescope to analyze TOI 1227 b’s atmospheric conditions. This planet orbits its star at an extremely close distance, much closer than Mercury orbits the Sun, making it about a thousand times younger than Earth. The star’s intense X-ray radiation is depicted in computer simulations as a blue tail of gas streaming off the planet, illustrating the ongoing atmospheric loss.

Remarkably, if current conditions persist, TOI 1227 b could eventually transition from a gas giant to “a small, barren world.” This process, known as photoevaporation, highlights the significant impact of stellar radiation on planetary evolution.

Stellar Radiation and Planetary Evolution

The findings emphasize the critical role of high-energy stellar radiation in young planetary systems. Intense X-rays and ultraviolet light from active young stars can heat and subsequently blow away a planet’s atmosphere. Co-author of the study Joel Kastner notes that understanding exoplanets necessitates accounting for high-energy radiation such as X-rays. He likens the star’s output to “a hair dryer on an ice cube,” illustrating how the radiation gradually erodes the gas off the planet.

This phenomenon could explain why many intermediate-sized exoplanets appear to end up smaller or are stripped down to their core. As scientists continue to explore the dynamics of exoplanets like TOI 1227 b, these observations provide a rare glimpse into the formative stages of planetary evolution, shaping our understanding of how stars interact with their orbiting worlds.

The research contributes valuable insights into the processes influencing planetary atmospheres and their long-term survivability in the cosmos, paving the way for future studies in exoplanetary science.