The planet in question is a gas/ice giant similar to Uranus with a radius 6 times that of Earth (nearly 80,000 km in diameter) with an as yet unknown mass (although it must weigh less than half of Jupiter's mass at the most). It orbits a pair of binary stars with a period of 138 days. The binary it orbits is an F dwarf star with 1.5 the Sun's mass and an M dwarf with 40% of the Sun's mass, they orbit each other with a period of 20 days. For reference, this translates to the two stars orbiting much closer than Mercury's orbit (around 0.17 AU) and the planet with an orbit close to that of Venus (around 0.65 AU, according to my calculations).
This system is bound to another binary system of similar total mass (a G2 star similar in mass to our Sun and an M2 dwarf star with around half or less the mass of our Sun) at a distance of around 1,000 AU. At that distance the second binary system would merely be the brightest stars in the night sky of the planet. The two binary systems would orbit each other with a period of tens of thousands of years.
I've tried about 8 different ways to modelling that and so far all of them have the planet being ripped apart as soon as its orbit is elongated by the traversing between the two pairs of binaries. Bizarre doesn't begin to describe it.
This doesn't make sense to me. The two pairs of binaries are around 6 light-days apart. The gravitational forces they have on each other are miniscule, but they are persistent enough to cause the two systems to orbit each other with a period longer than the duration of human civilization.
Yes, and if you model the force on the planet when it travels between them it has a small tidal effect. Depending on the relative orbital planes of the planet and the second binary star system, that may occur any time from once per orbital period to once every 10,000 years. But now try to see how the planet stays in a stable orbit over a billion years. At least in the models I've been able to come up with the tidal effect is assymetric, which is to say the tweak to orbit of the planet is not counter acted by a symmetric tweak on the far side. Even starting with the 'suns' being effectively two point sources 1000AU apart in a bilaterally stable orbit. Trying to find a way to reliably orbit a planet around one of them stably is eluding me. If you can come up with some orbital parameters that work I'd love to see them.
Apologies for my skepticism, my estimate is that the distant binary star system would impart a force on a planet less than 5% that of Jupiter on Earth. Could you provide more details on your n-body simulations? Such as what code base you are using, etc.
Wow that´s great, I have always wondered how astronomers come to calculate the orbits of objects like asteroids or comets just knowing a small part of their movement. Modeling a system as complex as this double double, is just awesome (even if it´s not holding water yet).
What programs are you using? is there a book or web that explains to a layman how this is done?
The planet in question is a gas/ice giant similar to Uranus with a radius 6 times that of Earth (nearly 80,000 km in diameter) with an as yet unknown mass (although it must weigh less than half of Jupiter's mass at the most). It orbits a pair of binary stars with a period of 138 days. The binary it orbits is an F dwarf star with 1.5 the Sun's mass and an M dwarf with 40% of the Sun's mass, they orbit each other with a period of 20 days. For reference, this translates to the two stars orbiting much closer than Mercury's orbit (around 0.17 AU) and the planet with an orbit close to that of Venus (around 0.65 AU, according to my calculations).
This system is bound to another binary system of similar total mass (a G2 star similar in mass to our Sun and an M2 dwarf star with around half or less the mass of our Sun) at a distance of around 1,000 AU. At that distance the second binary system would merely be the brightest stars in the night sky of the planet. The two binary systems would orbit each other with a period of tens of thousands of years.