Eating planets makes the star Gliese 504 appear younger

Star system: 59 Virginis | Distance from the Sun: 57.4 light years

The Sun-like star GJ 504 presents a cosmic mystery: despite being roughly 2 billion years old, it rotates rapidly and possesses an intense magnetic field typical of a much younger star. This study investigates the theory that GJ 504 'rejuvenated' itself by swallowing a Jupiter-sized planet. 

By mapping the star's magnetic field and simulating its stellar winds, researchers found that the star's current high-energy state and rotation speed cannot be explained by normal aging. Instead, the data strongly supports a scenario where the gravitational pull of a planet caused it to spiral inward, spinning up the star and restarting its internal magnetic engine. The discovery of a second candidate, HD 75332, suggests that this 'planetary engulfment' may be a common way for older stars to regain their youthful vigor.

Scientific study

Eating planets makes you younger: The magnetic dynamo rejuvenation of GJ 504 by planetary engulfment (external link)