After taking about 10,000 images of the star with HATSouth and other telescopes, the researchers inferred the planet's transit around it. They concluded that it actually causes disruptive tides on the star that change its orbital speed. "The high planet mass, combined with its short orbital period, implies strong tidal coupling between the planetary orbit and the star. In fact, given its inferred age, HATS-18 shows evidence of significant tidal spin up," wrote the researchers.

The team believes that the system could become a laboratory of sorts to help scientists learn about planetary formation. They next want to compare the results with the few other hot Jupiter-style planets out there to more accurately predict how planetary tides affect stars and vice-versa. For instance, their calculations suggest that the planet will take a full extra minute to orbit the star in just 28 years. "HATS-18 is an extreme short-period planet which is among the best targets for testing theories of planet-star interactions," they say.