An oddly-behaving star led two UW astronomers to capture rare evidence of a collision between two planets in a distant solar system. The discovery could aid scientists in their search for worlds similar to our own.


An oddly-behaving star led two UW astronomers to capture rare evidence of a collision between two planets in a distant solar system. The discovery could aid scientists in their search for worlds similar to our own.

University of Washington astronomers were on the lookout for “stars behaving strangely” when an automated alert from pointed them to Gaia17bpp, a star that had gradually brightened over a 2 1/2-year period. But follow-up analyses indicated that Gaia17bpp wasn’t changing. Instead, the star is likely part of a rare type of binary system. Its apparent brightening was the end of a years-long eclipse by an unusual, “dusty” stellar companion.

Astronomers have long suspected that superflares, extreme radiation bursts from stars, can cause lasting damage to the atmospheres — and thus habitability — of exoplanets. A new study published in the Monthly Notices of the Royal Astronomical Society reports that they pose only a limited danger to planetary systems.

Astronomers have catalogued 126 years of changes to a binary star system called HS Hydrae. Analyzing observations from astro-photographic plates in the late 1800s to TESS observations in 2019, they show that the two stars in HS Hydrae began to eclipse each other starting around a century ago, peaking in the 1960s. The degree of eclipsing then plummeted over the course of just a half century, and will cease around February 2021.

UW astronomers Brett Morris and James Davenport assisted in new research on “Tabby’s Star,” named for Louisiana State University astronomer Tabetha Boyajian.