Anyone who has ever had to build a model of our Solar System for a science project knows one thing that makes the job easy – all of the planets orbit the Sun in the same plane. Imagine how hard this would be – and how much bigger the model would have to be – if the orbits of Venus, Mars and Uranus were horizontal while the rest were vertical? Now, imagine how this could possibly happen during the creation of a solar system. Impossible? Meet HD 3167 – a little brother of our Sun with three planets – two in horizontal orbits and one strange outlier flying perpendicular to the other two ... or is it vice versa?
“If you had a telescope and you were looking at the trajectory of the other planets in the system, they would be going vertically in the sky.”
University of Geneva astronomer Vincent Bourrier, lead author of the report published in the journal Astronomy & Astrophysics, described to The New York Times what one would see gazing at the sky from the surface of standing on the surface of HD 3167 b, c or d … if one survived landing on one of these uninhabitable exoplanets. Using ESPRESSO – an echelle spectrometer on Chile’s Very Large Telescope used for detecting unusual light diffractions – Bourrier and his team tracked the innermost planet, HD 3167 b, as it passed in front of its star and found its orbit was perpendicular to the polar orbits of the other two exoplanets in the system. This super-Earth planet is closer to its star than Mercury is to our sun – completing an orbit once a day. In fact, all three would be within the orbit of Mercury in our solar system – mini-Neptune HD 3167c takes 30 days and HD 3167d has an 8.5-day orbit. What knocked HD 3167 b 90 degrees out of orbital whack?
“A Jupiter-sized planet could be massive enough to tilt the planets.”
University of Exeter astronomer Shweta Dalal, who was not part of the study but has researched the HD 3167 system speculated to The New York Times that the cause is a yet-to-be-seen fourth planet the size of Jupiter whose gravity is twisting the orbits of HD 3167 c and d. HD 3167, located 150 light years away, is smaller and dimmer than the Sun so SyFy Wire says finding that disruptive planet may be impossible with current telescopes.
While we wait to see HD 3167 e, one can still impress their science teacher with a display of the perpendicular orbits of the exoplanets of HD 3167 – all it takes is a lot of glue, strong wires, foam balls and good balance.