Astronomers discover six (!) planets around a nearby star

The star HD110067 is 100 light years away from us and is therefore close. It now appears that this star is a lot more special than initially thought. Further research shows that this star is home to as many as six planets that dance around the star in a very rare resonant system. And they have been doing so for a billion years, undisturbed.

Most planetary systems are formed in a resonant system. This means that the planets exert regular forces on each other. This is how the inner planet rotates a in nine days around the star HD110067. For every three rounds that a makes, lays b two off. For every three rounds that b makes, lays c two off, and so on. Only the outer two have a different rhythm, they complete three laps where the predecessor can make four. The whole thing resembles a dance. The research has been published in the journal Nature.

Dancing stars
The planets found are classified as ‘sub-Neptunes‘, meaning they are bigger than Earth but smaller than Neptune. What makes the find extra special is that a resonant system has only been found twice before. This is because the mutual balance in such a system is very fragile. The planets can very quickly be disturbed by external forces. Consider, for example, another star that comes a little too close or a meteorite that hits one of the planets themselves with a huge impact.

Rafael Luque is a scientist who helped with the research. He says: “We estimate that approximately one percent of all galaxies have a resonant pattern. It is therefore very special that HD110067 has remained undisturbed for so long.” The find can therefore be called unique and an opportunity for scientists to conduct research into what an undisturbed planetary system looks like.

Quest
The system around the star HD110067 has been keeping scientists busy for quite some time. Signals were picked up by NASA’s as early as 2020 TESS-satellite from which it could be concluded that at least two planets were present. However, there was also a lot of data that scientists could not make chocolate out of. “This was the point where we decided to use ESAs CHEOPSsatellite,” says Luque. “This made it possible to spot a third planet. Once we were able to capture the pattern of the first three planets, it became clear that this was a resonant system. Then we could predict the orbits of the other planets.”

Previously obtained data was used for this, and what turned out? It all fit exactly. This is how perhaps the oldest dance ever discovered.