New Planetary Phenomenon Found: A Spinning Carousel of Worlds

The Planets

KOI-134 b and KOI-134 c 

The Discovery

Scientists have recently uncovered two planets in the KOI-134 system by reanalyzing old data from NASA’s Kepler Space Telescope. They originally believed this system had no planets, but the new study shows that two planets orbit the star in a surprisingly unique way—like a spinning merry-go-round.

Key Facts

The KOI-134 system includes two planets that orbit their star on different orbital planes. One of these planets shows large transit timing variations (TTVs), which cause its transits to shift by as much as 20 hours. Researchers have identified this system as the first known to exhibit such unusual orbital behavior.

The Details

More than ten years ago, Kepler observed the KOI-134 system and detected possible signs of a planet. But because the planet’s transits didn’t follow a regular pattern, the automated detection system marked it as a false positive. As a result, scientists didn’t analyze the signal further.

Now, a new research team has returned to this data and found something remarkable. They confirmed that the previously rejected signal actually belongs to a real planet, KOI-134 b, and also discovered a second planet, KOI-134 c. These planets interact in a dynamic and unusual way.

KOI-134 b is a warm Jupiter—a gas giant similar in size to Jupiter but orbiting closer to its star. The planet’s transits don’t follow a strict schedule. Instead, they shift by up to 20 hours earlier or later than expected. This happens because KOI-134 c’s gravity pulls on KOI-134 b, affecting its orbit and timing.

By studying these transit timing variations through simulations, researchers identified KOI-134 c as a planet slightly smaller than Saturn. It orbits even closer to the star than KOI-134 b and plays a key role in the gravitational dance between the two.

KOI-134 c remained undetected in earlier observations because it orbits on a tilted orbital plane, different from that of KOI-134 b. This inclination prevents KOI-134 c from passing in front of its star from our point of view, making its transits invisible. The two planets orbit on planes that differ by about 15 degrees – a significant angle known as a mutual inclination. Moreover, due to their gravitational interactions, these orbital planes don’t remain static – they tilt back and forth over time.

Another fascinating aspect of this system is its orbital resonance. The two planets are locked in a 2:1 resonance, meaning KOI-134 c completes two orbits in the time it takes KOI-134 b to complete one. KOI-134 b takes roughly 67 days to orbit its star, while KOI-134 c completes its orbit in about 33 to 34 days.

With their shifting orbital planes, strong transit timing variations (TTVs), and resonance, KOI-134 b and c create a dynamic orbital dance. Their motion resembles two wooden ponies bobbing up and down on an old-fashioned merry-go-round, circling their star in a complex and captivating rhythm.

Fun Facts

Though astronomers initially dismissed KOI-134 as a false positive, this reanalysis of Kepler data revealed a compact, energetic planetary system. It is the first known multi-planet system that isn’t flat, shows significant TTVs, and features oscillating orbital planes.

Most known planetary systems do not exhibit high mutual inclinations between closely spaced planets. These inclinations are rare and difficult to measure, making this discovery particularly valuable. By capturing data on mutual inclination, resonance, and TTVs, astronomers now have a much clearer view of planetary system dynamics – insights that are typically hard to obtain.

The Discoverers

A research team led by Emma Nabbie of the University of Southern Queensland published their findings on June 27 in Nature Astronomy. Their paper, titled “A high mutual inclination system around KOI-134 revealed by transit timing variations,” presents the groundbreaking analysis of the KOI-134 system. The study drew on data from NASA’s Kepler Space Telescope and included contributions from researchers at the University of Geneva, University of La Laguna, Purple Mountain Observatory, the Harvard-Smithsonian Center for Astrophysics, the Georgia Institute of Technology, and NASA’s Kepler mission team.