by Sophie Jenkins
London, UK (SPX) Apr 30, 2024
Researchers at Durham University have identified a new mechanism potentially explaining the orbital decay of exoplanets around sun-like stars, a phenomenon observed in systems such as WASP-12b.
The study, published in The Astrophysical Journal Letters, highlights how stellar magnetic fields may significantly influence the gravitational tides between these stars and their closely orbiting 'hot Jupiter' exoplanets. Hot Jupiters, massive and gaseous like our own Jupiter, orbit their stars in just a few days and are drawn progressively closer over billions of years.
Traditional tidal theories have struggled to fully account for the rapid orbital decay seen in these systems. The Durham-led research, in collaboration with the University of Leeds and Northwestern University, suggests that the strong magnetic fields within certain stars can effectively dissipate these gravitational tides.
The interaction between the tidal waves generated by the planets and the stellar magnetic fields results in the conversion of these tides into magnetic waves, which then dissipate outwardly.
Dr. Craig Duguid, the study's lead author, said, "This new mechanism has wide reaching implications for the survival of short period planets and particularly hot Jupiters. It opens a new avenue of tidal research and will help guide observational astronomers in finding promising targets to observe orbital decay. It is also quite exciting that this new mechanism could be observationally tested within our lifetime."
The findings are expected to assist astronomers in targeting stars that might host hot Jupiters with similar decaying orbits, potentially offering further insights into the dynamics of these distant worlds and the dispersal of tidal energy within the stars.
Research Report:An Efficient Tidal Dissipation Mechanism via Stellar Magnetic Fields
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