In a discovery that’s fit for a movie, Northwestern University astronomers have directly imaged a Tatooine-like exoplanet, orbiting two suns.
While obtaining an image of a planet beyond our solar system is already rare, finding one that circles two suns is even rarer. But this new world is extra exceptional. It hugs its twin stars more tightly than any other directly imaged planet in a binary system. In fact, it is six times closer to its suns than other previously discovered exoplanets.
The discovery provides an unprecedented look at how planets move and form around multiple stars. It also offers a rare glimpse into how stars and planets orbit together, enabling astrophysicists to test theories of planet formation in complex systems. The study was published in The Astrophysical Journal Letters. Also published in the journal Astronomy and Astrophysics, European astronomers at the University of Exeter report the same discovery.
“Of the 6,000 exoplanets that we know of, only a very small fraction of them orbit binaries,” said Northwestern’s Jason Wang, a senior author of the study. “Of those, we only have a direct image of a handful of them, meaning we can have an image of the binary and the planet itself. Imaging both the planet and the binary is interesting because it’s the only type of planetary system where we can trace both the orbit of the binary star and the planet in the sky at the same time. We’re excited to keep watching it in the future as they move, so we can see how the three bodies move across the sky.”
An expert in exoplanet imaging, Wang is an assistant professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences. He also is a member of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). Nathalie Jones, the CIERA Board of Visitors Graduate Fellow at Weinberg and member of Wang’s research group, is the study’s lead author.