A surprising new discovery has come from a fresh look at data from NASA’s retired Kepler Space Telescope.
Astronomers have found that the KOI-134 system, once thought to have no planets at all, actually has two planets orbiting their star in a very unusual way—like wooden horses on a merry-go-round.
More than ten years ago, scientists noticed strange signals in the data from KOI-134.
They suspected a planet might be orbiting the star, but the timing of the planet’s transits (when it crosses in front of the star and blocks a bit of the star’s light) didn’t make sense.
The signals were so irregular that the planet was dismissed as a false positive by Kepler’s automated system, and the system was not studied any further at that time.
However, thanks to NASA’s policy of making all its data publicly available, researchers today can revisit old records with better tools and understanding.
In a new study led by Emma Nabbie from the University of Southern Queensland, scientists took another look at KOI-134’s data and found not just one, but two planets.
The first planet, now confirmed as KOI-134 b, is a “warm Jupiter”—a planet similar in size to Jupiter but orbiting closer to its star, making it warmer.
This planet’s original transits looked strange because they were arriving up to 20 hours early or late.
These odd timings are caused by what scientists call transit timing variations, or TTVs. In simple terms, KOI-134 b is being tugged back and forth by the gravity of a second planet in the system.
That second planet, KOI-134 c, is a little smaller than Saturn and orbits closer to the star than KOI-134 b. It went unnoticed for years because it travels on a tilted path and doesn’t cross in front of the star from our point of view—so it doesn’t create a visible transit.
What makes this system so fascinating is the way these two planets interact. Their orbits are tilted about 15 degrees from each other—a fairly large difference for planets that are close together.
As they tug on each other with gravity, their orbital paths actually tilt back and forth over time, a bit like a seesaw.
The two planets are also in what’s called a 2-to-1 orbital resonance. That means KOI-134 c makes two trips around the star for every one trip KOI-134 b makes. KOI-134 c takes about 33 to 34 days to orbit, while KOI-134 b takes about 67 days.
All of this—tilting orbits, changing transit times, and the orbital resonance—creates a movement pattern around the star that looks a bit like two bobbing carousel horses going around in rhythm.
This discovery marks the first known case of a compact planetary system with such a noticeable tilt between close planet pairs, along with strong TTVs and orbital resonance. These kinds of systems are rare and difficult to detect, making KOI-134 a truly special find.
The study was published in Nature Astronomy and involved scientists from multiple international institutions, including NASA and several universities. It shows how reexamining old data can lead to exciting new discoveries about the complex and surprising ways planets move in space.
Source: NASA.
