Life supporting planet orbiting neutron star in binary system with main seq star?

[Zuni]

I write short sci-fi stories, and want to write one in the setting above ^^. A large (3-ish G) planet orbiting around a non-quasar neutron star in binary (almost same mass) orbit with a giant, nearly supernova star.

Quick plot summary:

Ship stranded on this planet. Rescue mission sent, discovers primitive life. While taking samples, a meteorite shower destroys some of the rescue ship's equipment, forcing the people to take apart the original ship and use it to repair the rescue ship. They take off and get into orbit, when the giant star finally goes supernova. The ship gets blown out far away, but the supernova had wiped all their electrical equipment. One member manages to regain electric power and reroutes it fully to a single escape pod, which he escapes in and leaves the others behind. The black hole formed by this begins to suck the rest of the crew in, and after a few shenanigans, everybody dies.

But I don't know much about astronomy or whatever area this applies to. I want to make it realistic as possible, and I'm completely open to discussion. Some main questions are:

How far away would the planet have to be from the neutron star?

What kind of atmosphere/terrain would this sort of planet have?

What sort of life forms would you likely find?

Thanks!

[Kryten]

If a star is converted to a black hole, it doesn't suddenly start 'sucking things in'-it has exactly the same gravity as before. In fact it has less, as it'll have lost mass in the supernova.

[TheSaint]

If a star is converted to a black hole, it doesn't suddenly start 'sucking things in'-it has exactly the same gravity as before. In fact it has less, as it'll have lost mass in the supernova.

This^

If you want to read a really good story about life around a neutron star, read The Integral Trees by Larry Niven.

[Zuni]

Good point.

So, it would be exactly the same, pretty much? Would it affect planetary orbits? Mess up the binary system? Or just be the same but small and dense?

[Kryten]

The black hole won't make that much difference-as you say, it'd be pretty much the same except smaller and denser-but the supernova that produces it'd be another story entirely. I'm not sure about messing up the binary system, but the planets would be pretty screwed. Any planets reasonably close (up to maybe ten times the earth-sun distance) to the supernova will simply be destroyed; anything further out will be have their orbits messed up sufficiently for most of them to be outright flung out of the system, and of course will be burnt to cinders in the process.

[Zuni]

most of them to be outright flung out of the system

So maybe instead of being pulled in, having a gas giant approaching at mach 69?

[Ralathon]

So maybe instead of being pulled in, having a gas giant approaching at mach 69?

When you're that close to a supernova you've got bigger problems than a gas giant collision. There's a bubble of overheated solar plasma rushing towards you at 10% of c, not to mention the ungodly amount of radiation. If you don't get away quickly you'll be burned, ripped to shreds and die from instant radiation poisoning all at once.

[Zuni]

When you're that close to a supernova you've got bigger problems than a gas giant collision. There's a bubble of overheated solar plasma rushing towards you at 10% of c, not to mention the ungodly amount of radiation. If you don't get away quickly you'll be burned, ripped to shreds and die from instant radiation poisoning all at once.

Yes, but light itself takes minutes to get to Earth. If the neutron star was shielding the ship partially, and the binary system isn't a close together one, then it would take a long time for the explosion to arrive.

[Ralathon]

Yes, but light itself takes minutes to get to Earth. If the neutron star was shielding the ship partially, and the binary system isn't a close together one, then it would take a long time for the explosion to arrive.

Yea, it takes 8 minutes for light to get from the sun to earth. But, that means that if the sun goes nova right now, we'll only know that in 8 mins. And radiation travels at arbitrary speeds between 0 and c. So your geiger counters would go insane just a few seconds after you see the sun go supernova.

The planet flinging out of orbit will happen, but it happens so slowly it's insignificant. As long as most of the solar mass remains within the planet's orbit it won't change course at all in fact (Divergence theorem). So you'll have hours before the orbit begins to drift and even then you have days before it'll cause trouble. The radiation and shockwave are a much more pressing issue.

[Zuni]

Yea, it takes 8 minutes for light to get from the sun to earth. But, that means that if the sun goes nova right now, we'll only know that in 8 mins. And radiation travels at arbitrary speeds between 0 and c. So your geiger counters would go insane just a few seconds after you see the sun go supernova.

The planet flinging out of orbit will happen, but it happens so slowly it's insignificant. As long as most of the solar mass remains within the planet's orbit it won't change course at all in fact (Divergence theorem). So you'll have hours before the orbit begins to drift and even then you have days before it'll cause trouble. The radiation and shockwave are a much more pressing issue.

Say you have quantum communication or something, so you can instantly receive messages. The second the star explodes, the communication device sends a message to your ship, warning you of the nova. Considering how far and fast we technologically advance, do you think that by the time we could have gone to a faraway star system and invented faster-than-light communications, we could with that amount of warning throttle up and escape far enough away to survive? I am assuming that when on full power this ship has working radiation shields (To get that out the way).

[Wesreidau]

So a ship is stranded on a planet orbiting a neutron star. Why did that ship go there? How did they communicate for a rescue? Who in their right minds would attempt a rescue? Wouldn't everyone getting the signal look at the star about to go supernova and go 'nope'? Why would any ships at all be near a supernova that close to its end of life?

But more importantly, who's the protagonist, who's the antagonist, and why should I care about their miserable lives? If this is a story about a big explosion and a rocket ship and everyone dying, did the people matter? Did the rocket matter? Did the explosion matter? Why does the story matter?

If the story has more depth than you're letting on, and I'm sure it does, then focus on that. Focus on when she betrays him and he knew all along and left a radio switched on in the escape pod so he could finally tell her about his feelings as his ship grows cold and dark and lonely. Figure out the whiz-bang science nonsense after you have the squishy flesh and blood figured out, and if you don't yet understand flesh and blood, study it until you do. Until then the science fiction is just window dressing. If the story doesn't stand on its own in a Greek odium three thousand years ago, it won't stand today.

If you want to write, there's no substitute for hard advice. Take this in the good nature it was intended.

[christok]

I'd suggest making your terrestial planet the moon of a gas giant instead. There are many reasons:

- One is that the gas giant could have somewhat shielded the moon against the formation of the neutron star (through its magnetic field and by just being in-between for the worst part). This could give you greater flexibility in the kind of life which could be present after a reasonably short time but don't think it makes the damage small in any way.

- Another is that you can use the far side of the gas giant as the "safe" zone (I'm being optimistic here) instead of just saying the ship got blown out far enough to survive. (Have your ship rapidly approaching the safer side when the star starts to go boom.)

- The creation of severe fluctuations and radiation bands in the magnetic field of the gas giant during the explosion makes the reasoning behind your electrical failures more obvious.

- Multi-body dynamics makes it generally easier to throw things around. The interaction between the moon, the gas giant, other moons, etc. could be what sends your ship towards the black hole. In particular, I think the expanding atmosphere of the gas giant (due to heat from the supernova) could create an unexpected aerobrake. Use this to send your crew towards a moon encounter they didn't see coming and gravity-asist them out of the gas giant SOI and into the black hole.

I'm a little iffy on that last point since I'm not that clear on the details of gas giant atmosphere but hey, it's probably better than what you get in most sci-fi.

I've been severely underplaying the damage from a supernova. Might I suggest anything smaller? Besides the obvious explosion, debris from a supernova is so hot it puts out around 10^42J of optical energy over the year following the explosion. Your supernova survivor is probably getting fried no matter which direction he goes.

If you want to stick with a supernova the best I can think of is parking the lifeboat in a deep canyon on a tidally locked moon, facing the planet, and using some sort of hybernation chamber for a number of years. It might not work if the atmosphere swells enough to deorbit tidally locked moons or if drag from the supernova debris does the same.

Keep in mind that your planet must be quite far from the neutron star, since anything close in would have been devoured during the red giant phase. Also, stars lose a lot of mass late in life and planets drift a little out. In particular, the maximum possible mass of a neutron star is probably less than three solar masses while the minimum mass of a star that goes supernova (and thus to a neutron star) is around 8 solar masses and up. These numbers are actually a lot more debatable than what Discovery Channel et al. will lead you to believe.

One terminology issue: A giant star on the verge of core collapse is not "main-sequence". The latter refers to a star in the hydrogen-buring phase. It swells up around the time it starts to burn heavier elements, if at all. In the case of one that goes supernova, it will have already burnt elements up to about silicon in the core. The final, silicon-burning phase will last days and the core collapse is on the order of a second.

Keep your secondary star a giant no matter what you change. Its habitable zone is farther out (and larger) allowing you to have more plausible lifeforms.

Also, what Wesreidau said.

[Zuni]

Thanks for all the info, christok. I understand that a star that big is no longer a main sequence, it was a typo that I wrote that in the title.

Something other than a Supernova? I'm not actually sure what it could be then, I want a sufficiently large explosion coming out of a big star (I'm of simple taste).

Maybe, if a neutron star and giant are so different in solar mass then it could be in a bit of a one-sided binary system, with the neutron star orbiting the giant more than the giant orbiting it. Does this seem about right? Or would it be even more unbalanced?

Wesreidau, don't worry, I have a little antagonist/protagonist/tricksy/booboo thing going on too, but there's no point explaining all of that on a space forum I just want to find out a way of making sufficient explosions and drama and fire and stars and black holes, etc. Once I have the basic science, then I will certainly work on a detailed story that makes you love the characters (When they DIIIE!).

[Wesreidau]

Good, I'm glad we understand each other.

[christok]

Thanks for all the info, christok. I understand that a star that big is no longer a main sequence, it was a typo that I wrote that in the title.

Something other than a Supernova? I'm not actually sure what it could be then, I want a sufficiently large explosion coming out of a big star (I'm of simple taste).

Maybe, if a neutron star and giant are so different in solar mass then it could be in a bit of a one-sided binary system, with the neutron star orbiting the giant more than the giant orbiting it. Does this seem about right? Or would it be even more unbalanced?

The giant does not have to be more massive than the neutron star if it isn't required to go supernova. Any star can enter the giant phase if it is sufficiently massive to ignite helium fusion--about half a solar mass is sufficient. However, such a small star has a very long life. The ideal mass of a star is the so-called "Fundamental Stellar Mass" (denoted M-subscript-*), which balances various physical laws to produce a star which is massive enough to achieve and maintain fusion reliably and small enough to not blow itself up early on. It's around 1.85 solar masses--the sun's proximity to the Fundamental Stellar Mass is perhaps a part of why we humans can exist. For a simple boom you'd want something bigger than the Fundamental Stellar Mass.

As for what to do, it is very difficult to pick a stellar event which doesn't completely destroy your ship. (That 10^42J/year I spoke about? That's a hundred million suns right next to you.) My best suggestion would be a regular, non-super nova in a trinary star system. The largest has already exploded (stripping some mass from the others in the process) to create your neutron star. The other two are a white dwarf slightly less than half a solar mass and a slightly more massive red giant. The dwarf and giant are orbiting one another and spiraling together--the dense white dwarf is already stealing mass from the giant. These two together orbit the neutron star at a considerable distance. The planet is in an elliptical orbit around the neutron star. You can excuse its presence so close to a supernova remnant because it was originally orbiting one of the other stars.

When the white dwarf has taken enough mass from the giant, a helium flash occurs. (See the wiki page on helium flash for a brief introduction.) If your gas giant is behind the neutron star at this time, you might be able to hand-wave the physics sufficiently to get within a few orders of magnitude of survival. Remember that mass will be lost and temperatures raised in the nova. You could land on an icy moon and drown.

A gas giant should have high metallicity because the original supernova would have reduced its mass, especially hydrogen and helium.

It's okay if you make the physics only approximately correct and the circumstances unlikely. Otherwise it's just "everyone dies".

[Zuni]

It's okay if you make the physics only approximately correct and the circumstances unlikely. Otherwise it's just "everyone dies".

I'm just imagining that. "The crew was getting ready for bed, when all of a sudden everybody died. The end."

Thanks for the advice!

[ZetaX]

Current physics predict nothing like your "quantum communication", as all transmission of information is bounded by c via relativity.

[vexx32]

I suggest you look up quantum entanglement, good sir

(and yeah, I don't understand exactly how the hell they circumvent the speed of light limit for information transfer, but as I recall, it's hella complicated)

[Starwhip]

Another good read from Larry Niven: Neutron Star

Describes accurately what would happen close to a star like that. Maybe you could put those effects in your story.

[Smidge204]

I suggest you look up quantum entanglement, good sir

(and yeah, I don't understand exactly how the hell they circumvent the speed of light limit for information transfer, but as I recall, it's hella complicated)

It's not information transfer with entanglement, so nothing has violated the "universal speed limit."

=Smidge=

Edited November 22, 2013 by Smidge204

[Pigbear]

quantum morse code is possible with entanglement.

[Technical Ben]

If a star is converted to a black hole, it doesn't suddenly start 'sucking things in'-it has exactly the same gravity as before. In fact it has less, as it'll have lost mass in the supernova.

Yeah. It's sad and true. There is a possible work around this, but it's convoluted (orbits and such I guess).

The sad truth is, it's not the exciting things (black holes) that kill you in the end, or are they scary things (black holes are not scary), it's the normal and mundane (suffocation in space, fire, electrical failure, freezing).

Hence why I've tried to keep plot devices as background scenery and discussion and perhaps a driving force, but people are the main concentration of my stories. Though I do suffer badly from LOTS of plot devices. That and I generally could not take out 1 of my characters from a story, let alone all of the crew.

Hope the story goes well. I can't really comment on the science, as I try hard science myself, and don't know how routed you are in the current plot/setting. If it was me, I'd make the concentration all about the supernova, and the black hole the afterthought/deep impression. The black hole is not their problem, or what they are running from, but it is all that will be "remembered" or left over. The supernova is their death dealing enemy, the black hole is just their skeleton remains... (fade to eery sci-fi music).

PS, I've toyed with a similar idea planned for Space Engineers Machina (or anything really, but SE could let me do the artwork in 3d quickly). The story has FTL, and FTL coms. A star goes supernova, so the local corporation pulls out mining and coms from near by systems. Thing is, stars are 3+ LY away from each other, then more so for surrounding systems. So they have years to move equipment. Not so much time for within the system though!

PPS, QM transmission of data is impossible in all instances. Sorry, tis the facts. But you can just "handwave" it or "lampshade" it. We write sotries for "what ifs" and "imagine if". FTL is the imagination. As long as your clear it's possible in the story, and happy our real world is different, both the writer and the reader can get on well. It's when people wish the imaginary to be real, or make a story all about imagination (it becomes too random) and no facts (consistencies) it gets more difficult. So you can keep your story consistent and allow FTL, as long as you don't try to involve relativity, as the two are not compatible. Might get away with throwing out locality instead, but that's a whole other ball game, so I just stick to lampshading and what if'ing.

PPPS, what Wesreida said. I'll refrain from posting my current sci-fi short story (very amature I hasten to add), but I do what Wesreida says. While I've used some reasonable plot device vehicles to move the characters around the story, at the end, the enemy is human nature.

Edited November 22, 2013 by Technical Ben

[Kerbart]

Another good read from Larry Niven: Neutron Star

Describes accurately what would happen close to a star like that. Maybe you could put those effects in your story.

That has more to do with being very close to an object of very dense matter than the pecularities of the Neutron star itself.

The advice I'd give to the OP is this: think very carefully about the environment. Why all the complications? As Arthur Clarke once put it: good science fiction is when you take everyday life but change one aspect, and then write a story on how different life is due to that aspect. The story seems to be ship is stranded, bad things happen due to internal struggles with the crew. To what extend do you need a complex system for that? What is it that a meteor shower cannot accomplish? Remember the rule of Chekhov's gun: don't introduce details that are not needed in the story.

[Technical Ben]

I'll agree with Kerbart. I'll put lots of stuff in the background mind, nothing wrong with Chekhov's gun if it's clear it's just scene dressing... but even then, it would sign post (make the reader know) the house belongs to a shooter/hunter/farmer. It will have an effect.

Think of the situation and why and how you wish to move it. I'll admit I'll want to put in a cool scene. So how do we get there? It has to fit the reality and consistency of the characters and setting (can be a fictional setting, and not real life, but needs consistency). What's the simplest or most prominent reason to add? Is there one already set up?

Which is where the black hole complicates things if made part of the plot (I guess it can still be in the background). The Super Nova could break consistency. Fixing that could be complex (needs super shields on the ship or certain orbits of the planets). Where as some other type of nova, or a "burp" from the sun (I think it could be possible one would be "eating" the other, so mass transfers and changes in size/flares would exist) might do.

I guess this does not apply to "space opera" though, or to "magic" or "dues ex machina". It's just I personally prefer consistent stories. I've stopped watching my favorites when they have devolved into constant "dream sequences" (Far Scape seemed to be really susceptible to this, and even ended the entire thing on a dreamscape plot device).

All this commenting on stories, space and explosions, reminds me I still need to post up my ending chapter to my story!

Edited November 22, 2013 by Technical Ben

[Technical Ben]

Ps, might be relivant for your story: http://what-if.xkcd.com/