Tabby’s Star may have a giant-planet culprit: new study on its dimming

A new study on KIC 8462852, better known as Tabby’s Star, has just come out, and it points to a possible giant planet that could help explain the star’s long-running, irregular fading. The main clue, according to the paper, is a single transit seen in September 2019. It lasted roughly 21 hours and looks consistent with a companion around ten times Jupiter’s mass. Tabby’s Star has stood out for more than a decade because its dips in brightness don’t look like normal planetary transits, and some of those drops have reached about 22%.

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Lead author Cristina Madurga-Favieres and her colleagues say a planet that large could stir up comets, planetesimals, or other material, creating uneven dust clouds and giving the system a plausible source for its messy dimming. Madurga-Favieres also noted that no transiting companion had been detected there before.

For people who’ve followed the Tabby’s Star mystery, this also fits the bigger picture. Citizen scientists with Planet Hunters first flagged the star in 2015 using NASA’s Kepler data. The alien megastructure speculation lost momentum later, once follow-up observations showed that more blue light was being blocked than red. In 2016, astronomer Tabetha Boyajian raised more than $100,000 through Kickstarter for follow-up work. And over time, other ideas, from comet swarms to a destroyed exomoon, stellar changes, and a nearby companion, have more and more given way to explanations built around dust and debris.

You can read the new findings in the latest study, though the paper is careful on one point: a single transit still doesn’t confirm the planet.