Astronomers Puzzled by 'Radically Different' Solar System

Planets around HD 3167 have perpendicular orbits
By Rob Quinn,  Newser Staff
Posted Nov 8, 2021 1:25 PM CST
Astronomers Spot Planets With Perpendicular Orbits
An artist's rendering of HD 3167 c.   (NASA)

In some solar systems, including our own, planets orbit around the star's equator. In others, they orbit around the star's poles—and in one that has puzzled astronomers, both kinds of orbit have been observed. Researchers say that in the HD 3167 system around 150 light years away, the innermost planet, HD 3167 b, has an orbit like the planets in our system but the outer two, HD 3167 c and d, have a polar orbit perpendicular to that of HD 3167 b, the New York Times reports. In a study published in the journal Astronomy & Astrophysics, researchers say the strange mix of orbits may be the results of "interactions with an outer companion"—a planet the size of Jupiter that they haven't observed yet, or another unknown force.

"This is something radically different from our own solar system," lead researcher Vincent Bourrier from the University of Geneva tells the Times. He says that if you were on one planet with a telescope "and you were looking at the trajectory of the other planets in the system, they would be going vertically in the sky." IFLScience notes that system's planets "appear rather ordinary" despite their unusual orbits: HB 3167b is classed as a "super-Earth," about five times the size of our planet, while the outer two are Neptune-like. All three are considered too close to the system's star, an orange dwarf, for there to be any possibility of life. Bourrier says the first-of-its-kind finding shows that "planets can evolve in really, really different ways." (More exoplanet stories.)

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