Can solar systems orbit one another?

[Logos&Eidos]

My WIP to apply a genre label would be science-fantasy or space-fantasy. However since truth is in so many cases stranger than fiction, I endeavor to handwave as little as possible. Which brings me here to ask a question of the more physics versed.

The know worlds of mine would technically be classified as a trinary star system(stars don't exist in the verse, but planets do form around and orbit immensely heavy objects) however the image of a normal solar system is not what I Invision. What I see is three star systems orbiting each other with a small gap between them. Would such a configuration be possible.

 

[Queshire]

In Binary star systems two stars orbit each other. I suppose a trinary star system would be possible however balancing the gravitational force would be hell to do. That's just stars though, entire solar systems would be even harder because you'd have each star trying to "steal" the other two's planets. I really don't see it happening naturally though with Science-Fantasy you have your pick of explanations from magic, to artifacts, to having it be just an unexplained mystery.

 

[Penpilot]

I found this online educational game a while ago. Super Planet Crash - Can you feel the gravity?

In it you try to build a stable solar system. You can add various types of planets and stars to the system and see how they all interact. As mentioned by Queshire, with all those bodies interacting with each other, it becomes unstable. I tried to build a trinary star system and either there would be a planetary collision or plants would get ejected.

I don't know if what you envision is possible, but any way, the site might give you an idea of the complex balance involved.

 

[psychotick]

Hi,

Yes there are many binary and trinary star systems. But you asked about the solar system, and that's more tricky. As the planets orbit their primary stars / suns, they tend to move closer to and further away from the other suns. And when they come closer those other suns pull their orbits out of circular or elliptical. It makes them generally unstable, giving them highly eccentric orbits. And occasionally a planet may be pulled completely out of its orbit to orbit another sun. When that happens complete destruction isn't usually far away. The complete destruction of planets by opposing gravity wells would also lead to the creation of huge asteroid fields.

To add to your woes, the effects of being caught between three intense gravitational fields will be felt on the planets. There will be massive techtonic shifts, and the planet will be heated up simply by the movement of the crust. They probably won't be life sustaining.

Those planets that fare best in such a system would be the ones lying close in to their star - the inner planets.

It does depend of course. If one sun is massive and the other two minor, then instead of three suns orbiting one another, you may well end up with two suns orbiting the large one, probably at greater distance than the planets of that larger sun. In this sort of system, where two suns effectively become planets, the effect on the inner planets of the system would be greatly lessened. The outer planets would still be stuffed of course, but Earth is an inner planet.

All of this however is guesswork, nd it is possible that there is a trinary system somewhere out there in which the perfect arrangement of stars and planets has been found which allows for stability. But I would think that would be very rare.

Cheers, Greg.

 

[Logos&Eidos]

A better way to phrase my question would be, can a solar system have a satellite star-system which in turn has it's own satellite star system?


To present my idea in a more clear manner, the known worlds aren't so much a trinary system as they are three separate solar systems, the two smaller in orbit around a third larger with a small gap between them. The systems swapping planets between them really isn't a problem for me...though imagine that the process would be hell for anybody living on them. Is their anyway for this arrangement to form without having to handwave it?

 

[Terry Greer]

As Psychotick says - if you're happy losing the outer planets and only having the core ones close in then you might get away with it - especially if you also add brown dwarfs to the mix - perhaps radiating to their satellites in the infra red rather than visible light.
A really large jovian planet could even in theory become a proper short-lived sun (as happens to Jupiter in Clarke's 2010) with a bit of help.

 

[Queshire]

Hmmm.... It should certainly be possible. I mean, moons orbit planets who orbit a star in turn. The only difference between that and planets orbiting stars who orbit another star in turn is a measure of scale but man, what a measure of scale it is. If you have the primary star be some sort of uber-star which is to other stars what stars are to the planets I think the average reader will accept that. Is that remotely scientifically possible? I have absolutely no clue, but I love the idea of a star^2 anyways!

 

[ThinkerX]

I visit another site dedicated to the discovery and investigation of extra-solar planets.

There are a number of planets in multiple star systems. In some, the planet orbits one star, in a very few the planet orbits both stars.

As yet, there are no systems listed with planets orbiting both stars...though that could change, as there are many planet detection projects.

That said...

Binary systems are fairly common. Something on the order of a third of sun-like stars are in binary systems.

Trinary systems are much rarer, but do exist, and I believe planets have been discovered or are strongly suspected in one or two of them.

Systems with more than three stars are very rare, but also exist.

That said...distances between stars vary in multiple star systems. Many of these systems have very high eccentricity - on the order of 60%, making for very elongated orbits. In quite a few systems, the distances are so severe - on the order of hundreds or thousands of astronomical units - the stars do not orbit, though they are gravitationally linked. Usually, this translates to a sort of side to side 'fishtail' movement.

With most triple systems, what you usually have is a pair of fairly close set companions - within a couple dozen AU - and the third component being several hundred to several thousand AU distant. From the planets I've seen listed and discussed on the other site, it should not be impossible or even unlikely for each of the three stars to possess planets of their own.

 

[Logos&Eidos]

Satellite galaxy - Wikipedia, the free encyclopedia A better phrasing for my question is, just as galaxies can have smaller ones as satlites. Could a star system have a smaller one as it's satellite?

As for how my cosmos works...it's weird man. There are no stars! Stellar scale nuclear fusion for what ever reason is just not a naturally phenomenon. All the heat light and raw material come from these white hole like eruptions into "our" dimension from a perpetual storm beneath the Skien of the cosmos; inspired very loosely by quantum-foam and zero-point energy. What regular planets orbit are in essence, these condensates of this dense energy rich exotic matter; since I removed stars from the equation I needed something for planets to form around and orbit.

Why not just hand wave everything and do what I want, after all I've depart significantly from normal reality? Because true is stranger than fiction, why just come up with an explanation if a possible one already exist.

 

[ThinkerX]

Could a star system have a smaller one as it's satellite?

Yes. In this universe there are many multiple star systems with a larger (more massive) central component being orbited by a smaller star. If the distance is sufficient, then in theory at least, each star could have a system of planets. Several systems with planets orbiting one star of a pair have been discovered.

 

[Logos&Eidos]

Yes. In this universe there are many multiple star systems with a larger (more massive) central component being orbited by a smaller star. If the distance is sufficient, then in theory at least, each star could have a system of planets. Several systems with planets orbiting one star of a pair have been discovered.

Thanks!

My idea was for three solar systems orbiting one another, in a biggest to smallest arrangement. But it's seeming like that wouldn't work to well. The smaller bodies would just get pulled in by the larger one becoming a standard trinary system, instead of a solar system with a smaller satellite that in turn has it's own even smaller satellite system.

But now I am beganing to feel that rather than being smaller, if the stars at the heart of these systems were roughly the same mass then they might entre into an equilibrium. Where the stars masses balance out so that they remain relatively close but at the same time don't merge into a true trinary system.

 

[ThinkerX]

Ok...a real multiple star system I have been eyeing for a SF story of my own - someday. Kappa Tucanae:

This is a system with four stars. The largest (A) is an F class subgiant, with a much smaller M class red dwarf orbiting something on the order of every couple hundred years. A good couple thousand AU from this pair are two more stars, both K class, of about equal mass, orbiting a common center of gravity with a period of about thirty years. Any of these stars could have planets. The K class pair are the most likely to have habitable (earthlike) planets; the F star is becoming unstable, and the M dwarf...any planet within its habitable zone would be tidally locked (one face always aimed at the star...unless said world is on the cold side. To date, no planets have been discovered orbiting any of these stars. The biggest strike against the system is it may be a bit too young...probably only a couple billion years old, most theories say a system with a habitable earthlike planet would need to be at least 3 billion. On the other hand, a few reputable SF authors have put habitable worlds in orbit around Sirus, which is way to young, and will 'die' before it gets anywhere near that age.

Your 'biggest to smallest' arrangement is workable, though most likely the outmost (smallest) component would either have an orbit measured in terms of millennia, or it would simply show 'Common Proper Motion' (CPM), 'sharing space' with the other two.

Your idea for stars of the same mass...well, I find that puzzling. If two are of the same mass (and the Gods of Orbital Mechanics are being benevolent) they could have a stable circular orbit about a common point (otherwise, they'll have a highly eccentric orbit (30% - 60% being the most common). The third star would most likely be a CPM companion.

Or you could just go with three stars sharing CPM. There are many systems like that. In this case, the distances would be on the order of hundreds to thousands of AU, though there would still be a bit of gravitational nudging.

 

[Logos&Eidos]

Ok...a real multiple star system I have been eyeing for a SF story of my own - someday. Kappa Tucanae:

This is a system with four stars. The largest (A) is an F class subgiant, with a much smaller M class red dwarf orbiting something on the order of every couple hundred years. A good couple thousand AU from this pair are two more stars, both K class, of about equal mass, orbiting a common center of gravity with a period of about thirty years. Any of these stars could have planets. The K class pair are the most likely to have habitable (earthlike) planets; the F star is becoming unstable, and the M dwarf...any planet within its habitable zone would be tidally locked (one face always aimed at the star...unless said world is on the cold side. To date, no planets have been discovered orbiting any of these stars. The biggest strike against the system is it may be a bit too young...probably only a couple billion years old, most theories say a system with a habitable earthlike planet would need to be at least 3 billion. On the other hand, a few reputable SF authors have put habitable worlds in orbit around Sirus, which is way to young, and will 'die' before it gets anywhere near that age.

Your 'biggest to smallest' arrangement is workable, though most likely the outmost (smallest) component would either have an orbit measured in terms of millennia, or it would simply show 'Common Proper Motion' (CPM), 'sharing space' with the other two.

Your idea for stars of the same mass...well, I find that puzzling. If two are of the same mass (and the Gods of Orbital Mechanics are being benevolent) they could have a stable circular orbit about a common point (otherwise, they'll have a highly eccentric orbit (30% - 60% being the most common). The third star would most likely be a CPM companion.

Or you could just go with three stars sharing CPM. There are many systems like that. In this case, the distances would be on the order of hundreds to thousands of AU, though there would still be a bit of gravitational nudging.

Thanks, I made all the "stars" in the system roughly the same sizes,because I was concerned that my idea of three star system acting as satellites, orbiting from largest to smallest with a small gap(relatively speaking) between them couldn't work; and that the two smaller systems would get pulled in by the the third bigger resulting in a standards trinairy system. My thought was that if all the stars were of near equivalent mass then they would balance each other out,neither drifting to close or being able to pull away.

Good to know that my original idea of a solar system with two smaller satellites actually is possible! The stars having centuries long orbits around each other is not a problem.

My next problems are going to figuring out the distances and lengths of the stars orbiting each other. Then filling each system with planets; I need a least one per race.

The Cyrannus systemThe Twelve Colonies of Kobol - Battlestar Wiki of nBSG might be of interest to you it has the two sets of binary star.

 

[ThinkerX]

OP and others might find this interesting. Nice music too.

https://www.youtube.com/watch?v=up_MqNBv0FE

A few years ago, I had a collaboration of sorts going with the guy who put that movie together.

 

[Ravana]

My idea was for three solar systems orbiting one another, in a biggest to smallest arrangement. But it's seeming like that wouldn't work to well. The smaller bodies would just get pulled in by the larger one becoming a standard trinary system, instead of a solar system with a smaller satellite that in turn has it's own even smaller satellite system.

Short answer: yes, it's possible. The key is the distance separating the main bodies–i.e. that it be great enough that at least some smaller bodies can orbit them.

The problem is that this may not be quite what you had in mind. This would, in effect, be three separate tightly-spaced solar systems, rather than "one" system. That may still work for you; the question would be why you wanted such an arrangement in the first place, what you wanted to accomplish with it (how things appear in the sky, travel time between them, etc.). "Planet-swapping" would be highly unlikely, although it is at least theoretically possible for a planet to have a stable figure-eight orbit around two stars (successful computer models have been produced… though they only take into account the orbits, not how the system might have formed, as far as I know).

There is at least one known example of the sort of thing you're thinking of in general terms, though: Castor, in Gemini. Originally thought to be one star (of course), in the 1600s it was discovered to be a widely-separated binary; later, spectroscopic analysis showed that each of these two stars is itself a binary; recently, it was discovered that there is a third, distant companion to the paired pair–which, it turns out, is also a binary. Thus, you have three sets of pairs orbiting one another, each pair individually stable… gravitationally identical to what you have in mind. If on a somewhat larger scale than you probably want. As far as I know, Castor is still the only sextuple system we've discovered, though there's some reason to think that Mizar (a double binary) and Alcor (a binary) in Ursa Major are gravitationally linked… though the distance between the two sets is at least half a light year, so while they might be "one" system in an astrophysical sense, they're effectively two nearby ones for pretty much any other purpose.

However, there's no reason to believe you need quite that scale: it has been shown that the stars of Alpha Centauri (a double plus a distant third) would be capable of having nearby companions–small ones, at least, since if they were large we would have spotted them by now. And, in fact, there have been as-yet unconfirmed observations indicating that ACen B might have at least one planet orbiting it, albeit far closer than anyone would likely find comfortable; the data on that are still under question.

So, yeah, it could happen.

 

[Logos&Eidos]

Short answer: yes, it's possible. The key is the distance separating the main bodies—i.e. that it be great enough that at least some smaller bodies can orbit them.

The problem is that this may not be quite what you had in mind. This would, in effect, be three separate tightly-spaced solar systems, rather than "one" system. That may still work for you; the question would be why you wanted such an arrangement in the first place, what you wanted to accomplish with it (how things appear in the sky, travel time between them, etc.). "Planet-swapping" would be highly unlikely, although it is at least theoretically possible for a planet to have a stable figure-eight orbit around two stars (successful computer models have been produced… though they only take into account the orbits, not how the system might have formed, as far as I know).

There is at least one known example of the sort of thing you're thinking of in general terms, though: Castor, in Gemini. Originally thought to be one star (of course), in the 1600s it was discovered to be a widely-separated binary; later, spectroscopic analysis showed that each of these two stars is itself a binary; recently, it was discovered that there is a third, distant companion to the paired pair—which, it turns out, is also a binary. Thus, you have three sets of pairs orbiting one another, each pair individually stable… gravitationally identical to what you have in mind. If on a somewhat larger scale than you probably want. As far as I know, Castor is still the only sextuple system we've discovered, though there's some reason to think that Mizar (a double binary) and Alcor (a binary) in Ursa Major are gravitationally linked… though the distance between the two sets is at least half a light year, so while they might be "one" system in an astrophysical sense, they're effectively two nearby ones for pretty much any other purpose.

However, there's no reason to believe you need quite that scale: it has been shown that the stars of Alpha Centauri (a double plus a distant third) would be capable of having nearby companions—small ones, at least, since if they were large we would have spotted them by now. And, in fact, there have been as-yet unconfirmed observations indicating that ACen B might have at least one planet orbiting it, albeit far closer than anyone would likely find comfortable; the data on that are still under question.

So, yeah, it could happen.

Thank you, three systems in very closes proximity is precisely what I wanted,I've been posting here and elsewhere to find out if that arrangement is even remote possible; and I'm ecstatic to find out that yes it actually could! As for why I wanted that arrangement it's about finding a compromises between imagination and workability. I love the feel of galaxy spanning space-opera however the scale of such a story when I actually though about it, just gave me a massive headache. So perverse the worlds hopping feel,and the ability to use the term outer rim, i compressed everything down into three star systems lined up biggest to smallest. I've even kept the Inter-dimensional drive, it's just so slow that would take quit a while to travel between the system of the three-system.

 

[ThinkerX]

So perverse the worlds hopping feel,and the ability to use the term outer rim, i compressed everything down into three star systems lined up biggest to smallest. I've even kept the Inter-dimensional drive, it's just so slow that would take quit a while to travel between the system of the three-system.

With a system that compact you would not need an 'inter-dimensional' or 'warp' drive. Consider the continuous 1 gravity acceleration table on this site:



Calculations for science fiction writers - Space travel with constant acceleration - nonrelativistic

Assuming you wanted to slow down (deceleration), you could probably cross the long axis of the sort of triple system you envision in something on the order of a couple of months. Fuel could be a problem, though. However:

NASA Technical Reports Server (NTRS) - Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

This is a 'propellentless drive,' which is highly controversial at the moment - if it works as advertised, it does a sort of end run around the 'conservation of momentum' (laws of thermodynamics). Because this whole topic is of long standing interest to me, I read not only the original NASA paper but a pile of related stuff over the past few weeks. End of the NASA paper, the authors put forth hypothetical manned missions to Mars and Saturn employing this drive. A spacecraft using this drive could reach Mars in less than a month (relative orbital positions depending) and make it to Saturn (roughly 9.5 AU) in something on the order of eight months. Allowing for both acceleration and deceleration, a spacecraft using this drive could probably fully traverse the long axis of your system in a couple of years.

However:

This is an 'in space' drive only. Its advantage is it doesn't really need fuel, but it doesn't produce a lot of thrust. You would not use this drive for landing or leaving the surface of a planet with significant gravity. Top speed, even with a bit of fudging, would be about 0.1 gravities (might have to rotate the ship to provide higher gravity). Another drive would be needed for planetary liftoffs.

You *could* use this drive for actual interstellar travel - trips spanning a good couple dozen light-years. However, even with relativistic effects, trip time for the crew would still be a decade or more (I have yet to run the numbers). It would also be hazardous: hitting a meteor the size of a marble at half light-speed releases energy on the order of a large H-Bomb.

 

[Logos&Eidos]

With a system that compact you would not need an 'inter-dimensional' or 'warp' drive. Consider the continuous 1 gravity acceleration table on this site:



Calculations for science fiction writers - Space travel with constant acceleration - nonrelativistic

Assuming you wanted to slow down (deceleration), you could probably cross the long axis of the sort of triple system you envision in something on the order of a couple of months. Fuel could be a problem, though. However:

NASA Technical Reports Server (NTRS) - Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

This is a 'propellentless drive,' which is highly controversial at the moment - if it works as advertised, it does a sort of end run around the 'conservation of momentum' (laws of thermodynamics). Because this whole topic is of long standing interest to me, I read not only the original NASA paper but a pile of related stuff over the past few weeks. End of the NASA paper, the authors put forth hypothetical manned missions to Mars and Saturn employing this drive. A spacecraft using this drive could reach Mars in less than a month (relative orbital positions depending) and make it to Saturn (roughly 9.5 AU) in something on the order of eight months. Allowing for both acceleration and deceleration, a spacecraft using this drive could probably fully traverse the long axis of your system in a couple of years.

However:

This is an 'in space' drive only. Its advantage is it doesn't really need fuel, but it doesn't produce a lot of thrust. You would not use this drive for landing or leaving the surface of a planet with significant gravity. Top speed, even with a bit of fudging, would be about 0.1 gravities (might have to rotate the ship to provide higher gravity). Another drive would be needed for planetary liftoffs.

You *could* use this drive for actual interstellar travel - trips spanning a good couple dozen light-years. However, even with relativistic effects, trip time for the crew would still be a decade or more (I have yet to run the numbers). It would also be hazardous: hitting a meteor the size of a marble at half light-speed releases energy on the order of a large H-Bomb.

Well given how much friction imagine that aether has, high-speed acceleration really wouldn't be possible. at least not with out some kind of low friction protective coating to put on ships.

 

[Ravana]

Well given how much friction imagine that aether has, high-speed acceleration really wouldn't be possible. at least not with out some kind of low friction protective coating to put on ships.

Ah, but with aether, you won't need a propellantless drive: you can use a ramjet.

If you do have an interplanetary/interstellar medium, you're gonna need protection no matter what your acceleration is like: friction is still friction. Most practical might be something which polarizes the aether, creating a bow shock in front of the nose of the craft. Two problems there: first, you won't be able to use a ramjet, since you need some way to get the aether into the engines; second, a non-electrically-neutral interplanetary medium would hose up just about every other aspect of your astrophysics. I'd consider the second one the bigger of the two… heh.

You might be able to fudge things by saying the ships have really good thermal transfer units, which take the heat of the friction and send it to the engines where it's used to accelerate the aether. Yes, it's another twist on "perpetual motion," but at least it gives a veneer of pseudo-scientific explanation, deals with the friction, and gives something which can break when the plot demands it… always a positive. The disadvantage of that approach is that it does not provide protection against large foreign objects–micrometeors, astrostarlings, what have you. Hitting anything bigger than a molecule at a significant fraction of c will definitely hose up your day, if you don't have a way to shunt it aside first. (For that matter, I suspect even hitting good-sized molecules could be problematic.) So you may be stuck with some variation on a force field regardless.

Of course, even most "hard SF" stories hand-wave such details away, so unless you think you can make it function as part of your plot–and not simple exegesis–probably best not to sweat it too much.

By the way: if you are willing to allow speeds close to c, there are actually quite a few stars out there which are not co-orbital but which are within a light-year of one another, so that might open additional possibilities for you. (Sorry, can't recall examples offhand–most only have catalog numbers, not real names.) Sol is surprisingly isolated when it comes to nearest neighbors, as it turns out. If I can locate any of the old star maps I did (ages ago, by hand, on graph paper)–or better still, the calculations which led to them–I'll see if I can come up with some of the numbers for you… I do recall that there were almost no stars in our vicinity whose nearest neighbor was not less than four light years (the distance to our own nearest).

Or you could skip waiting on me and see someone else's version of the same thing:

Actual Maps - 3-D Starmaps

These were made for gaming, I believe (well, so were mine…), but the data's all the same, and it's the examples I was after, anyway. Reading a 2D map as 3D is always tricky… but if you scroll down about 80% of the way, you'll see amongst the creator's products not only actual maps but also "node maps"–which show the stars in relation to one another, along with distances (in parsecs). Disadvantage to this approach is the map only shows links to the three nearest neighbors (some stars have more than three lines leading to/from them: "nearest" is not a transitive relation), but, again, it's the examples that matter here.

[Marginally off-topic: should anyone be a C. J. Cherryh fan, this is an extremely enlightening graphic, by the by… if, for instance, you assume the maximum range your star drive can handle is on the order of 2.5 parsecs. Which I discovered after I made my own maps–with precisely that working assumption, in order to give space some "geography." One look at what I'd produced, and I realized I was staring at the same thing I'd seen following the title page of Downbelow Station. ]

 

[ThinkerX]

Logos...

...unless it is essential for plot reasons, you might want to consider ditching the 'aether,' and going with ordinary vacuum instead.

Ravana beat me to the ramjet suggestion. And with aether filled space...friction and heat build up is going to be a major issue. Even at the comparative snails pace used by our space probes, the hull temperatures are going to be ...really dang hot...