During the concluding phase of their main sequence life, stars with mass comparable to the Sun experience a transformative evolution. This evolutionary process is likely to affect the surrounding planetary systems. As the star expands in its post-main-sequence stage, astronomers anticipate that most exoplanets detected to date may be engulfed by the growing star.
An artist’s impression of a sun-like star engulfing a giant exoplanet. Image credits: International Gemini Observatory / NOIRLab / NSF / AURA / M. Garlick / M. Zamani
Utilizing data from NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers Edward Bryant and Vincent Van Eylen studied 456,941 stars that have just commenced their post-main sequence phase.
By employing a computer algorithm, they targeted giant planets with short orbital periods (those that complete an orbit in less than 12 days) and searched for consistent dips in brightness that would indicate these planets transiting in front of their host stars.
They discovered 130 planets and planet candidates, including 33 previously unknown, closely orbiting these stars.
The researchers observed that such planets are less likely to exist around stars that have expanded and cooled sufficiently to be categorized as red giants (more evolved stars), implying that many of these planets might have already been destroyed.
Dr. Bryant, an astronomer at University College London and the University of Warwick, stated: “This provides compelling evidence that as stars progress beyond the main sequence, planets can rapidly spiral out of existence.”
“This topic has been debated and theorized for some time, but we can now observe this phenomenon directly and quantify it at the level of stellar populations.”
“We expected to observe this phenomenon, but we were still astonished by how effectively these stars can consume nearby planets.”
“This destruction is believed to stem from a gravitational tug-of-war between the planet and the star, known as tidal interactions.”
“As the star evolves and expands, these interactions intensify.”
“Just as the moon influences the Earth’s oceans, creating tides, planets also exert a pull on their stars.”
“These interactions decelerate the planet, reducing its orbit and causing it to spiral inward, ultimately resulting in its disintegration or absorption by the star.”
“In the coming billions of years, our sun will expand and transform into a red giant,” mentioned Dr. Van Eylen, an astronomer at University College London.
“Will the planets in our solar system endure this transformation? Our findings suggest that, in some instances, planets do not survive.”
“Earth may be better off than the giant planets much closer to the stars we examine.”
“However, we only analyzed the initial part of the post-main-sequence phase, spanning the first one or two million years. There is still ample opportunity for stellar evolution.”
“Unlike the giant planets lost in our investigation, Earth has the potential to endure the Sun’s red giant phase. However, life on Earth is likely to be extinguished.”
The team’s paper was published on October 15, 2025, in Royal Astronomical Society Monthly Notices.
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Edward M. Bryant and Vincent Van Eylen. 2025. Determine the impact of post-main sequence stellar evolution on the population of passing giant planets. MNRAS 544 (1): 1186-1214; doi: 10.1093/mnras/staf1771
Source: www.sci.news
