Simulations show how planets accrete stellar wind from aging stars and may become detectable

Star system: HD 219415 | Distance from the Sun: 540 light years

As stars like the Sun age and evolve, they lose mass through strong stellar winds, which can affect the planets orbiting them. This study used computer simulations to explore how much material planets can accrete from the wind of a star as it goes through its red giant and asymptotic giant branch phases. The simulations covered planets with masses from half to thirteen times that of Jupiter, at distances of 5, 10, and 20 astronomical units from their star.

The results show that planets closer to the star and with higher masses accrete more stellar wind material, but the total amount gained is still small compared to the planet’s original mass. However, the energy released by this accretion—called accretion luminosity—can be higher than the planet’s normal heat emission, making these planets potentially detectable, especially around aging stars where planets have not yet been confirmed. The study also found that wind accretion and wind drag have little effect on the planets’ orbits, but accretion remains important for their brightness. These findings help guide future searches for planets around evolved stars.

Key findings
- Planets orbiting aging stars can accrete material from stellar winds, especially if they are massive and close to the star
- The total mass accreted is small, but the resulting luminosity can make planets detectable
- Accretion and wind drag have little effect on planetary orbits
- Simulations match results for known two-planet systems
- The findings support the search for planets around red giant and AGB stars

Scientific study

Wind accretion onto planets orbiting an evolving Solar-like star and their detectability (external link)