Ancient Solar System: Tiamat The Brown Dwarf
You ever thought about what would happen if the Sun wasn’t just a lone ranger but had a partner to pair up with? 
And not just any sidekick, but a brown dwarf which is a failed star that’s too weak to keep those nuclear reactions active.
And it’s not just some crazy sci fi theory.
The destruction of the fifth planet becomes the starting point of the explanation of the origin of the asteroid belt and it provides plausibility for how the orbits of the planets were disturbed in the geologically recent past and how by this they developed into their present state
Ancient Solar System: Chaotic Catastrophe
Back in ol school ancient days, the Sun and this brown dwarf shared a center of mass with each other. 
Graham Hancock believes that the Babylonian stories of Tiamat represented this sister planet.
Tiamat is the salty sea goddess of ancient Mesopotamian mythology who gave birth to the gods and caused quite a ruckus.
She was the mother of all gods, but don’t think for a second that she was a nurturing type.
Traversing the solar system, the Red Sun holds disaster in store for all the inner planets, hitting hardest the fifth planet, Tiamat, of which only debris remains. Thus, the core of the considerations in this article deal with the fragmentation of the fifth planet, Tiamat, in the accretion disk of the transiting Red Sun.
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As for Tiamat’s appearance, we don’t a lot, but she’s depicted as a woman, a body of water, and a creature with a tail. 
Most ancient myths are based on cosmological events and elements within the distant past of our solar system.
A creature with a tail could symbolize a planet with its trail of debris visible with the naked eye in our ancient skies.
In another myth, Zeus fights with the Titan Typhon (accretion disk?) before he finally establishes himself as the new ruler of heaven. More specific than just being named as a dragon or a snake, in Greek mythology the figure of Typhon has all the characteristics of an accretion disc. The legend describes his appearance with two snakes forming the abdomen and with dragon-like heads.
Ancient Solar System: Feud Of The Planets
The destruction of Tiamat gave birth to the asteroid belt and created a whole lot of chaos in the solar system. 
The god Marduk which symbolized the Planet Jupiter had a hand to play in it.
Marduk aka Jupiter whipped up some winds to take Tiamat down and then shot an arrow right through her heart.
He then sliced her body into two pieces, using one to make the sky and the other to form the earth.
Tiamat – turned the heaven of the gods upside down and a new generation took over. Consequently, the gods Ra (Egypt) as well as Marduk (Mesopotamia) and Bolon-ti-ku (Mexico) don’t represent the first generation of gods. In ancient Greek mythology Zeus follows his father Kronos, whom he castrates with a sickle (accretion disc?).
Ancient Solar System: The Binary Star System
How would our solar system in a binary system with another massive solar body.
It would take one year for both the Sun and Tiamat to complete one orbit around their shared center.
And that time frame would depend on a bunch of stuff, like how far apart the two objects are and how much they weigh.
“We ran a series of statistical models to see if we could account for the relative populations of young single stars and binaries of all separations in the Perseus molecular cloud, and the only model that could reproduce the data was one in which all stars form initially as wide binaries,” said UC Berkeley astronomer Steven Stahler in June 2017.
https://www.sciencealert.com/our-sun-could-have-been-born-with-a-twin-called-nemesis
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For instance, if Tiamat is a lot lighter than the Sun, it would need to be snuggled up way closer to maintain a stable orbit.
That means the orbit would be super short, maybe just a couple of years, or even months!
Ancient Solar System: The Red Sun
Tiamat was moving through the accretion disk of the Red Sun, and something had to overcome its gravitational binding energy to make it explode.
Basically, we’re talking about the amount of energy it takes to hold a planet together.
If Tiamat was like Earth in mass and diameter, its gravitational binding energy would’ve been 2.4 x 10^32 joules.
To make this planet explode, we need something pretty darn big and moving pretty darn fast.
We’re talking a planetesimal with 5% of Earth’s mass, smashing into Tiamat at a velocity of 60.7 km/s.
To reach a quantitative understanding of how huge the body would have to be we examine a specific scenario: A planetesimal of the Red Sun exhibiting 5% of Earth’s mass (~3.2.1023 kg and thus four times heavier than the Moon), which smashes into the planet at a velocity of 60.7 km/s, would release a kinetic energy of 5.5.1032 J. This amounts to just twice the gravitational energy that pulls the planet together.
The accretion disk material helps enhance the energy input and break up the planet into fragments.
Now, after we blew up Tiamat, we gotta think about what happens to all the little pieces. 
Turns out, the momentum from the explosion actually affects the motion of the planet’s center of gravity.
Some calculations reveal that the planet’s motion slowed down by 2.5 km/s.
So, the explosion also messed with the Red Sun nearby, causing all sorts of chaos in the accretion disk.
And all the debris from Tiamat got scattered around space, forming the asteroid belt we know and love today.
The overlapping gravity of two suns and the hammering of the accretion disc prevented a re-condensation of the fragments but widened their cloud. Close encounters and hard collisions led each fragment and each piece of rubble onto a different course. In the end, only a small portion of the fragments remained on trajectories close to the former orbit of Tiamat. And, it is only these fragments that form today’s asteroid belt.
This was a cosmic mosh pit party.
Those asteroid fragments are all over the place and some of them go beyond Jupiter, while others cross paths with Mars.
It’s like a big ol’ game of space dodgeball.
References:
https://grahamhancock.com/eilinga6/
https://www.sciencealert.com/our-sun-could-have-been-born-with-a-twin-called-nemesis