This Strange Planet Has Three Suns and Orbits at Funky Angle
This illustration shows the planet KOI-5Ab moving across the face of a sun-like star that is part of a triple star system located 1,800 light years away in the Cygnus constellation. Caltech / R. Injured (Infrared Processing and Analysis Center or IPAC)
There are many curiosities in our universe, and new research has shed light on one such strange star system discovered more than a decade ago. Researchers have found a planet with three suns and an unusual kink in its orbit.
The planet KOI-5Ab was discovered in 2009 as the second candidate to be discovered by NASA’s then new Kepler mission. But nobody paid much attention to this particular world as Kepler continued to discover new and exciting planets.
But it’s valuable to go back in time to see things that others have overlooked, as the team at NASA’s Exoplanet Science Institute found. Chief scientist David Ciardi rummaged through the available data on KOI-5Ab from various telescopes and found it was worth a second look.
“KOI-5Ab was abandoned because it was complicated and we had thousands of candidates,” Ciardi said in a statement. “There was an easier choice than KOI-5Ab, and we learned something new from Kepler every day, so KOI-5 was largely forgotten.”
The most notable feature of KOI-5Ab is that it is part of a triple star system, which means that it orbits a star that is in an orbital pattern with two other stars. The elaborate dance of the three stars and the planet is already rare to find, and this system is even more unusual because the planet’s orbit is inclined at an angle.
The KOI 5-star system in this diagram consists of three stars with the designations A, B and C. The stars A and B orbit each other every 30 years. Star C orbits stars A and B every 400 years. The system is home to a well-known planet called KOI-5Ab, which was discovered and characterized using data from NASA’s Kepler and Transiting Exoplanet Survey satellite missions and ground-based telescopes. KOI-5Ab is about half the size of Saturn and orbits star A about every five days. Its orbit is inclined by 50 degrees relative to the plane of stars A and B. Astronomers suggest that this misaligned orbit was caused by star B, which gravitationally entered the planet during its evolution, distorting its orbit, and causing it to migrate inward. Caltech / R. Injured (Infrared Processing and Analysis Center or IPAC)
“We don’t know of many planets that exist in triple star systems, and this one is special because its orbit is crooked,” said Ciardi. “We still have many questions about how and when planets can form in multi-star systems and how their properties can be compared with those of planets in single-star systems. If we examine this system more closely, we may be able to gain some insight into how the universe makes planets. “
The inclination of the planet suggests that it and the stars in the system may not have formed from the same disk of gas and dust as usual. The current theory to explain the inclination of the planet is that one of the other stars disrupted the planet’s orbit and its gravity drove the planet to another plane.