From star-wrecking black holes to exploding comets, NASA’s Transiting Exoplanet Survey Satellite (TESS) has uncovered a number of surprises since it began searching the galaxy for exoplanets in 2018 -years away, all of these discoveries may be useful for its science fiction- exceed similar size.
The source, named TIC 168789840, is a system of six stars. That alone makes it a rarity, but what makes this sextuplet even more remarkable is that it is made up of three pairs of binary stars: three different pairs of stars that revolve around three different centers of mass, with the trio remaining gravitationally tied to each other and orbiting that galactic center as a single star system. Although a handful of other six-star systems have been discovered, this one is unique: it is the first in which the stars in each of these three pairings run in front of and behind each other, dwarfing the other member of his pre-eminent dance group, at least out of our line of sight Space telescope.
In other words, scientists have found a sextuple eclipse sextuple star system. The discovery, which went online this month, has been accepted for publication in the Astronomical Journal.
Exoplanets within the star cluster have not yet been confirmed, but if you lived on a world within, the night sky would be special, said Tamás Borkovits, an astronomer at the Baja Astronomical Observatory in Hungary and co-author. Every inhabitant of these worlds “could see two suns, just like Luke Skywalker on Tatooine,” said Dr. Borkovits, as well as four other very bright stars dancing around the sky.
But only one of the pairs could have planets. Two of the system’s binaries move extremely close together, forming their own quadruple subsystem. All the planets there would likely be ejected or devoured by one of the four stars. The third binary is farther away and orbits the other two about every 2,000 years, making it a possible exoplanetary haven.
Exotic star collections like this don’t just look cool. They refine and challenge our understanding of how multi-star systems are formed, said Patricia Cruz, an astrophysicist at the Center for Astrobiology in Madrid who was not involved in the work.
The depth and duration of the TIC 168789840 eclipses enable astronomers to determine the dimensions, masses, and relative temperatures of its stars – important information that can be incorporated into models of star formation. But even with these clues, the origin of this swirling six-star system will remain a mystery until we find others who like it.
“The system exists against all odds,” said Brian Powell, data scientist at NASA’s High Energy Astrophysics Science Archive research center in Greenbelt, Md., And lead author of the study.
NASA’s TESS satellite searches for exoplanets by looking for temporary dips in star light caused by a planet that we see orbiting in front of it. Dr. Cruz said, however, that scientists originally used the same light blocking principle as other telescopes to spy on stars obscuring other stars.
With this concept, Mr. Powell, in collaboration with Veselin Kostov, an astrophysicist at the SETI Institute, designed a neural network that could identify darkening binary stars using TESS data.
The neural network examined an archive of nearly 80 million records of changes in light intensity, far more than only humans could process. “Machine learning can turn that intractable dataset into something a human can work with,” said Powell. An abundance of multi-star systems was found last March, including the superlative TIC 168789840.
Late last year the data was shared with professional and amateur stargazers around the world, said Dr. Borkovits. Their efforts confirmed that TIC 168789840 was a sextuple system and helped clarify the properties, orbital dimensions, and paths of its stars.
Andrei Tokovinin, astronomer at the Inter-American Observatory Cerro Tololo in La Serena, Chile, and co-author of the study, suggests an explanation for the origin of the system: three stars that have formed in an expansive gas cloud and all orbit each other in a three-star -System. They later came across a dense lump of gas from the same cloud. This encounter caused disks to form around the original trio of stars, eventually giving each of them smaller companions.
Trying to unravel its origins is a worthwhile endeavor. But for Mr. Powell, “working with literally the most interesting data in the universe” is reward enough to just find that weird sextuplet.
“The very fact that it exists blew me away,” he said. “I’d love to just be in a spaceship, park next to this thing, and see it in person.”