Astronomers: Old stars like the Sun swallow up nearby planets

In a new study, researchers from the University of Warwick and College London (UCL) investigated the fate of planets orbiting aging stars. This research, which was conducted by analyzing nearly half a million star systems, shows that many close-orbiting planets will be destroyed in the stage of the star’s life when it becomes a red giant. The findings provide powerful observational evidence of this cosmic phenomenon that was previously only theorized.

When stars like the Sun use up their hydrogen reserves, they begin to expand and cool, becoming red giants. For the Sun, this dramatic transformation is expected to occur in about five billion years. Scientists believe that this expansion may lead to the destruction of Mercury, Venus, and possibly Earth, but so far there is little direct evidence to confirm exactly how it happened, or even if it is likely to happen.

Now, research led by scientists from the University of Warwick and University College London has shed new light on the fate of planets orbiting aging stars. Analyzing nearly half a million star systems, the team tried to find out how well the planets would survive the expansion of their host star into a red giant.

Their findings show that planets are much less common around stars that are in the final stages of their lives. This suggests that many close-orbiting planets are likely to be destroyed by the expansion of the star, and these findings provide strong observational evidence of this planetary destruction.

According to the study’s lead author, Edward Bryant, a distinguished research fellow in astrophysics at the University of Warwick who conducted much of the research at the Mullard Space Science Laboratory at University College London, these findings provide strong evidence that evolving stars can rapidly collapse and destroy nearby planets.

This phenomenon, long debated in theories, is now directly observable in a wide population of stars. Bryant explains that old stars can effectively swallow their nearby planets through tidal interactions. As the star expands, the gravitational pull of the planet slows down its rotation, and as a result, the planet gradually moves towards the star until it either disintegrates or is absorbed.

The research team focused on stars that have just entered the post-main sequence stage and have used up their hydrogen reserves. They identified only 130 planets and planet candidates around these stars, 33 of which were previously undiscovered. Focusing on stars that have cooled and turned into red giants, the researchers found that the probability of a near-orbiting planet around such stars is only 0.11 percent; A figure that is almost three times lower than the probability of a close-orbiting giant planet around main sequence stars.

The researchers also explain that in the next few billion years, the Sun will also become a red giant, raising questions about the fate of the planets in the solar system. The study shows that although some planets are destroyed in the early stages after the main sequence, Earth is more likely to survive than close-orbiting giant planets.

However, although the Earth itself may survive total destruction, life on it will be almost completely destroyed as the Sun continues to evolve. Although the study shows that the number of giant planets decreases as stars age, the few planets that remain in orbit close to red giants provide scientists with valuable information.

Bryant also points out that by determining the mass of these planets, researchers can better understand the forces that cause their collapse and destruction, and provide a more detailed picture of the processes that shape the fate of planets around aging stars.