Starship Asterisk*

Yale researchers have discovered a surprising link between the tilting of exoplanets and their orbit in space. The discovery may help explain a long-standing puzzle about exoplanetary orbital architectures. (Illustration: NASA/JPL-Caltech, Sarah Millholland)

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For almost a decade, astronomers have tried to explain why so many pairs of planets outside our solar system have an odd configuration — their orbits seem to have been pushed apart by a powerful unknown mechanism. Yale researchers say they’ve found a possible answer, and it implies that the planets’ poles are majorly tilted.

The finding could have a big impact on how researchers estimate the structure, climate, and habitability of exoplanets as they try to identify planets that are similar to Earth. ...

NASA’s Kepler mission revealed that about 30% of stars similar to our Sun harbor “Super-Earths.” Their sizes are somewhere between that of Earth and Neptune, they have nearly circular and coplanar orbits, and it takes them fewer than 100 days to go around their star. Yet curiously, a great number of these planets exist in pairs with orbits that lie just outside natural points of stability.

That’s where obliquity — the amount of tilting between a planet’s axis and its orbit — comes in ...

• Nature Astronomy (online 04 Mar 2019) DOI: 10.1038/s41550-019-0701-7