This giant exoplanet may open doors to exotic worlds

Anew study in the Astronomical Journal reports on the detection of the exoplanet HIP 67522 b, which appears to be the youngest hot Jupiter ever found. It orbits a well-studied star that is about 17 million years old, meaning the hot Jupiter is likely only a few million years younger, whereas most known hot Jupiters are more than a billion years old.

The planet takes about seven days to orbit its star, which has a mass similar to the Sun’s. Located only about 490 light-years from Earth, HIP 67522 b is about 10 times the diameter of Earth, or close to that of Jupiter. Its size strongly indicates that it is a gas-dominated planet. HIP 67522 b was identified as a planet candidate by NASA’s Transiting Exoplanet Survey Satellite (TESS), which detects planets via the transit method: Scientists look for small dips in the brightness of a star, indicating that an orbiting planet has passed between the observer and the star.

But young stars tend to have a lot of dark splotches on their surfaces – starspots, also called sunspots when they appear on the Sun – that can look similar to transiting planets. So, scientists used data from NASA’s recently retired infrared observatory, the Spitzer Space Telescope, to confirm that the transit signal was from a planet and not a starspot. The discovery offers hope for finding more young hot Jupiters and learning more about how planets form throughout the universe – even right here at home.

“We can learn a lot about our solar system and its history by studying the planets and other things orbiting the Sun,” said Aaron Rizzuto, an exoplanet scientist at the University of Texas at Austin who led the study.

“But we will never know how unique or how common our solar system is unless we’re out there looking for exoplanets. Exoplanet scientists are finding out how our solar system fits in the bigger picture of planet formation in the universe,” said Rizzuto.