New Study Reveals Aging Stars Can Destroy Planets Orbiting Close By

As stars age, they expand. This expansion poses a significant threat to planets orbiting close to their stars, as indicated by a recent study published in the Monthly Notices of the Royal Astronomical Society. The study highlights that planets in close proximity to their aging stars, especially those with orbits of 12 days or less, are at a higher risk of being engulfed or destroyed.

While the concept of dying stars consuming planets is not new, there have been limited comprehensive surveys to analyze the exact mechanisms and stages of a star’s evolution that put planets in jeopardy.

The research, based on a sample of over 400,000 post-main sequence stars, aimed to identify a decline in the planetary population around aging stars. Utilizing data from the Transiting Exoplanet Survey Satellite (TESS), the study identified 130 planets close to their stars, with thirty-three newly discovered candidate planets.

According to the findings, gas giants orbiting close to aging stars occur at a rate of approximately 0.28 percent. This rate slightly increases to 0.35 percent for stars entering the post-main sequence phase, but significantly drops to 0.11 percent for the oldest stars in the red giant phase. In essence, the aging process of stars is detrimental to planets in their vicinity.

Lead author Edward Brant from University College London and the University of Warwick emphasized, “This is strong evidence that as stars evolve off their main sequence, they can quickly cause planets to spiral into them and be destroyed. This has been the subject of debate and theory for some time but now we can see the impact of this directly and measure it at the level of a large population of stars.”

The study also revealed that planets with shorter orbital periods are more susceptible to destruction. Tidal forces between the star and the gas giant lead to the planet’s orbit decay, eventually spiraling inward towards its demise. Alternatively, these forces may tear gas giants apart, resulting in a dramatic end for these planets.

Our Sun is predicted to enter its post-main sequence stage in approximately 5 billion years. While Earth’s survival prospects are more promising compared to planets in close orbits like Mercury and Venus, challenges still lie ahead.

Co-author Vincent Van Eylen from University College London mentioned, “Earth is certainly safer than the giant planets in our study, which are much closer to their star. But we only looked at the earliest part of the post-main sequence phase, the first one or two million years of it – the stars have a lot more evolution to go.”

The team anticipates further insights into planetary destruction around aging stars through the PLATO mission, slated for launch in late 2026. This mission’s advanced planet-finding capabilities will enable the examination of even older stars in the red giant phase compared to those observed by TESS.

Original Source: Universe Today