7 Planets with a '3 Body Problem'

Concept art of the planet HD 188753Ab

Spoilers ahead

If you've watched "3 Body Problem" or read the excellent Cixin Liu books on which they are based, you must be familiar with the solar-powered conundrum at the center of the sci-fi series.

Life, it appears, is stranger than science fiction: There really are planets out there orbiting or within the vicinity of three stars, as scientists have discovered over the years. Majority of stars in the known universe are actually thought to be part of a binary system or a system with two stars. 

Triplet systems or more are less common and more special. Get ready for liftoff as we explore some heavenly bodies with something akin to three-body problems.

16 Cygni B b

This extrasolar planet was discovered to be part of a triple-star system as early as 1996. Also known as HD 186427 b, 16 Cygni B b (its name derives from its location 69 light years away in the constellation of Cygnus) revolves around the yellow dwarf 16 Cygni B every 799 days and has a mass equivalent to 1.78 Jupiters. A Sun-like star, 16 Cygni A, and a red dwarf, 16 Cygni C, complete this twinkling triumvirate.

HD 188753Ab

Echoing Ye Wenjie from her lonely mountain base on the show, Caltech astronomers in real life espied a planet in a tri-sun system from Hawaii's majestic Mauna Kea in 2005. This Jupiter-sized planet was said to float in the neighborhood of three stars collectively known as HD 188753. One of the scientists, Maciej Konacki, even likened the horizons on the planet to those of Tatooine in "Star Wars." Further reassessment in 2007 led to the conclusion that the existence of the planet could not be confirmed. Not all was lost for sci-fi fantasists though, for a year later, "3 Body Problem" was published as a novel.

HD 131399Ab

Three-hundred twenty light years from Earth, in the Centaurus constellation, a 16-million-year-old planet four times as colossal as Jupiter is in a cosmic dance with three stars, one twice the size of our Sun. Every 550 years (in Earth time), the planet circles a white giant in turn orbited by two stars, according to the astronomer who made the discovery in 2016. Alas, in 2022, scientists saw that this planet was non-existent; it turned out to be just another celestial object in the background, likely another star.

KOI-5Ab

After observing a dimming in the light of a trio of stars named KOI-5, some scientists attributed it to one gigantic explanation: an exoplanet called KOI-5Ab. It is said to orbit one of the stars in the system, KOI-5A, every five days at a skewed angle, a tilting caused by the neighboring star, KOI-5B. Every 400 years, a third star, KOI-5C, pays its sibling suns a visit. Enough travel time for the San Ti, too.

KELT-4Ab

Once thought to be part of a binary system, the planet KELT-4Ab was later found to be in a three-sun system. This scorching gas giant, spotted 685 light years away by scientists at the Harvard-Smithsonian Center for Astrophysics, revolves in just three days around a gargantuan star called KELT-4A. It in turn is orbited (every 4,000 years!) by KELT-4B and KELT-4C, which had both been mistaken for just a single star. 

LTT1445Ab

In 2019, Harvard-Smithsonian Center for Astrophysics researchers were excited to discover that the rocky planet known as LTT1445Ab would be transiting or passing between its star and observers on Earth. This planet is also a rarity in another way: It stands in a star system with three M dwarfs, the smallest types of stars. The biggest star in this system, in fact, is only one-fourth the size of our Sun.

Unnamed Planet, GW Orionis 

Unlike other celestial objects on this list, the gaseous planet within the GW Orionis system is said to be orbiting three suns all at once, making it closer in spirit to the world depicted on "3 Body Problem." The birth of the planet, discovered in 2021, could account for the misalignment in one of the dust rings that make the system so noticeable from telescopes; the rings together look like a bull's eye. 

The international team of scientists was right on target. Set 1,300 light years from Earth in the Orion constellation, this is the only true triple-sun planet, also known as a circumtriple, in the universe as we know it. 

You could only imagine the kinds of sunrise and sunset in this world, according to its discoverers. ("Star Wars" missed a trick, said one scientist.) Easy for us earthling bugs to romanticize, but for the Trisolarans, sunny days can be matters of life and death.