You Should Know About The Weird ‘Sextuple’ Star System Just Found By NASA Where Six Suns Eclipse Each Other

TESS previously revealed that Thuban, a former North Star, is also a eclipsing binary, as illustrated here. Three such pairs make up a newly discovered sextuple star system called TYC 7037-89-1. — TESS previously revealed that Thuban, a former North Star, is also a eclipsing binary, as … [+] illustrated here. Three such pairs make up a newly discovered sextuple star system called TYC 7037-89-1.

NASA’s Goddard Space Flight Center/Chris Smith (USRA)

Our Solar System is a normal, regular kind of star system where a bunch of planets orbit one star, right? Not so—it’s thought that most stars are in binary systems, where two Suns orbit each other.

Triple star systems are common, too, but a new and bizarre sextuple system just found by astronomers at NASA’s Goddard Space Flight Center ups the stakes.

TYC 7037-89-1 (also known as TIC 168789840), becomes the first known “sextuply-eclipsing sextuple star system.”

It’s comprised of three pairs of stars, with each pair eclipsing each other from the point of view of NASA’s exoplanet-hunting Transiting Exoplanet Survey Satellite (TESS).

TESS is up there to chart how the brightness of around 80 million stars changes over time, with software processing its data to identify any stars whose brightness dips—a sure sign that there may be planets going in front of it.

Using TESS data, the astronomers, whose research will soon be published in The Astronomical Journal and is also available as a pre-print online, found 100 star systems with potentially three or more stars.

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The most bizarre appears to be TYC 7037-89-1, a sextuply-eclipsing sextuple star system like no other.

Here’s what’s going on in TYC 7037-89-1:

How does the ‘sextuple’ star system work?

TYC 7037-89-1 is the first known sextuple star system where TESS can see the stars alternatively passing in front of each other. There are three pairs of binary stars, pair A, pair B and pair C:

Pair A and Pair C (inner): The stars in the inner A and C systems orbit each other every 1.6 and 1.3 days, respectively. The two pairs in this “inner quadruple system” orbit each other every four years.
Pair B (outer): The two stars in pair B circle each other every 8.2 days, together orbiting around the inner systems every 2,000 years.

Each pair comprises a primary and a secondary star. The primary stars in all three of binaries in TYC 7037-89-1 are all slightly bigger and more massive than the Sun and about as hot. The secondary stars are all around half the Sun’s size and a third as hot.

In fact, the pairs of stars are so similar that the researchers call them “triplets.”

This schematic shows the configuration of the sextuple star system TYC 7037-89-1. The inner quadruple is composed of two binaries, A and C, which orbit each other every four years or so. An outer binary, B, orbits the quadruple roughly every 2,000 years. All three pairs are eclipsing binaries. The orbits shown are not to scale. — This schematic shows the configuration of the sextuple star system TYC 7037-89-1. The inner … [+] quadruple is composed of two binaries, A and C, which orbit each other every four years or so. An outer binary, B, orbits the quadruple roughly every 2,000 years. All three pairs are eclipsing binaries. The orbits shown are not to scale.

NASA’s Goddard Space Flight Center

What is an eclipsing binary star?

It’s all about our line of sight. An eclipsing binary star system is typically a star system of two stars that orbit each other, or rather, they orbit around their center of mass. The only difference between an eclipsing binary system and any other binary star system is our line of sight—if TESS, or any telescope, can see the two stars eclipse each other, they’re called “eclipsing binaries.”

Why are eclipsing binary stars important?

While a planet moving across a star from our line of sight is the best way to find a planet, two stars eclipsing each other gives astronomers a lot more information about the actual star.

From observing the light-curves from eclipsing binaries astronomers can measure the sizes, masses and temperatures of the two stars, as well as their distance from each other and their distance from us.

Why is TYC 7037-89-1 an incredible find?

In the case of TYC 7037-89-1 the data might help astronomers untangle how the primary and secondary stars became so similar and also how the three systems became gravitationally bound.

It could give astronomers new insight into the formation, dynamics, and evolution of multiple star systems.

Where is TYC 7037-89-1?

It’s about 1,900 light-years away in the constellation Eridanus, the river. If you want to visualize where it is in the night sky, go outside after dark and find Orion high in the southeastern sky, and very bright star Sirius below. Rigel in Orion and Sirius will form a vast triangle with TYC 7037-89-1 as the third unseen point.

Wishing you clear skies and wide eyes.

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