Q for techies: photon torpedo induced supernova?

[Kuri]

Hi, I'm brand new here, so please be gentle.

I have searched the forum but not found a discussion that exactly answers a question I have.

Say we have a degenerate white dwarf star. It has enough mass to go supernova, but is not quite at that stage yet. Could a Federation starship push it into supernova by launching one (or more?) photon torpedo at it (or transport one into the star's core in order to detonate remotely)?

[The antimatter-matter reaction of photon torpedoes seems like a super-nuke in power to me, but I wonder if this will generate nearly enough energy to begin the process. Contemporary Earth nukes are a drop in the ocean compared to our Sun's energy right now.]

Then, assuming it is possible to do this, how instantaneous would the process be? The "helium flash" effect appears pretty rapid from the wikipedia article.

Then, assuming it is more or less instant, could the in-system starship survive the energy wave (lets assume its shields are at full power)? How about if it "rode" the wave like a surfer?

Finally, am I safe in assuming any planets in the system will be disintegrated by the supernova (and probably those in neighbouring systems too!)?

I thank you for your time.

Kuri the Tribble Overlord.

PS. I can't think of a way to say this without sounding rude, so I'll just go ahead: This is for a piece of fanfic I'm working on. I'm not a scientist. I'm not looking for a "sounds cool to me, go for it!" kind of reply. I know it sounds cool. I really want to get the science right - that's why I posted it on this forum. So, qualified answers, preferably (but not necessarily) with a source reference, would be very much appreciated!

PPS. I'm aware of the red matter method in the reboot film. This is more of an improvised solution using existing warheads.

 

[Christopher]

Say we have a degenerate white dwarf star. It has enough mass to go supernova, but is not quite at that stage yet. Could a Federation starship push it into supernova by launching one (or more?) photon torpedo at it (or transport one into the star's core in order to detonate remotely)?

I assume you're talking about a Type Ia supernova, in which a white-dwarf component of a binary system accretes matter from its companion until it become dense enough to undergo fusion. After all, an isolated white dwarf couldn't go supernova, since it's just the white-hot core of a lower-mass star that's already swelled into a red giant and ejected its outer layers.

My first thought was that if a white-dwarf binary component has accreted enough gas on its surface that it's on the verge of a fusion chain reaction anyway, it might be possible to trigger that fusion with a torpedo bombardment. But looking into it more closely, it looks like the reaction doesn't begin on the surface as I thought, but in the white dwarf's core because of the immense pressure it's under from the accumulated matter. I'm not sure how that could be triggered. The core would probably be way too dense to push a transporter beam through.

Then, assuming it is possible to do this, how instantaneous would the process be? The "helium flash" effect appears pretty rapid from the wikipedia article.

It looks to me like the process that leads to the explosion begins hundreds of years before the explosion actually happens. But the final trigger for the detonation isn't well-understood, so it's hard to say how long it would take.

Then, assuming it is more or less instant, could the in-system starship survive the energy wave (lets assume its shields are at full power)? How about if it "rode" the wave like a surfer?

This is one thing that Star Trek and most other screen sci-fi constantly gets wrong: There are no shock waves in space, at least not the kind that could affect a starship like a shock wave in water would affect a boat. A shock wave is a pressure front propagating through a medium, and space is a vacuum. The material of the medium isn't actually moving outward; it stays in place and the pressure wave passes through it. A surfer can only ride a wave if the surfer is already moving over the water at the same speed as the wave; otherwise the surfer will just bob up and down as the wave passes.

What you'd have in the case of a supernova is, first off, a front of hard radiation expanding at the speed of light; then a front of high-energy particle radiation expanding nearly as fast; and then behind that, a cloud of gas expanding outward relatively more slowly. It's those first two bursts of radiation (which would be effectively simultaneous if you were right there in the system) that you'd have to worry about the most, and they propagate at effectively (or actually) the speed of light. So if you can get away at warp, you're completely safe, and if you're stuck at impulse, you're dead. Pretty much no middle ground there, and no need for any fancy "surfing" move even if it were possible.

Finally, am I safe in assuming any planets in the system will be disintegrated by the supernova (and probably those in neighbouring systems too!)?

Certainly not like Romulus in the '09 movie. The nearer ones might be vaporized or melted, I suppose, but more distant ones might just be lethally irradiated.

 

[Kuri]

Awesome. I knew this was the right place to ask!

So, to summarise...

1. It needs to have absorbed its partner in a binary system in order to be "triggerable" Got it.
(Glad I checked - I thought from the wikipedia that white dwarfs were before the red giant stage.)

2. Ship needs to escape at warp speed or it's toast. Got it.

3. Planets nearer to the star get vaporised. Perfect, as it happens. Gives the crew a moral dilemma.

Thank you so much for your help.

Kuri

 

[Christopher]

1. It needs to have absorbed its partner in a binary system in order to be "triggerable" Got it.

Not the whole partner, just enough of its atmosphere to accumulate to the point that it triggers fusion. You remember TNG's "Evolution"? The binary star where one member accumulated gas from its companion and erupted every hundred-and-something years? That's what we call a nova. Eventually, a periodic nova binary can get to the point where the eruption is big enough to blow up the whole white dwarf -- and most likely its companion star along with it -- and that's a Type Ia supernova.

(Glad I checked - I thought from the wikipedia that white dwarfs were before the red giant stage.)

No, just the opposite. A star like the Sun swells to a red giant, casts off its atmosphere, and leaves a white dwarf behind, a white-hot, slowly cooling ember. If that white dwarf is part of a close binary, then it can become a nova/supernova star as discussed. (Stars larger than about 9 Solar masses go red giant, then blow up in a Type II supernova and leave behind a neutron star, a degenerate core far denser than a white dwarf. If they're larger than 30 or so solar masses, the core will be dense enough to collapse all the way into a black hole.)

3. Planets nearer to the star get vaporised. Perfect, as it happens. Gives the crew a moral dilemma.

Well, if you're worried about life on the surface, that's doomed regardless of whether the planet itself survives. Sci-fi likes to blow up entire planets because it's dramatic, but if you think about it, life only exists on a very, very thin layer on the surface of a planet, so all you have to do to render a planet lifeless is to wipe out that surface layer, which is orders of magnitude easier to do than actually disintegrating the entire mass of the planet.

 

[Sgt_G]

A shock wave is a pressure front propagating through a medium, and space is a vacuum.

Space near a stellar body is not a true vacuum, so you could still have a pressure wave. But also, we don't know how such an explosion effects things in sub-space. If you go by the movie, the sub-space shock wave can be quite devastating, and travels much faster than the speed of light.

 

[Kuri]

Christopher said: "Well, if you're worried about life on the surface, that's doomed regardless of whether the planet itself survives."

Actually the planet is already lifeless. But it has sites of archeological interest from the extinct civilisation. The dilemma was to be that triggering an astro-geological disaster like this would wipe out the specie's legacy before it can be properly preserved and studied. Like nuking Egypt. The tactical officer will argue "The needs of the living come first; we gotta do this!"

By the way... is it possible that a white dwarf has enough mass on its own to go supernova without the need for a former binary twin? It can work both ways for me. They just come to the system after the binary is absorbed, if needed.

@Christopher and Sgt_G I'm actually more interested in the resultant energy wave, as stated in the opening question.

All fascinating stuff. Glad I came here!

Kuri

 

[SPCTRE]

okay my first read of the thread title was "Q (as in John de Lancie) for Furries" and I was like "dude"

 

[Avro Arrow]

(Glad I checked - I thought from the wikipedia that white dwarfs were before the red giant stage.)

Main-sequence type G stars like our sun are often referred to as "yellow dwarfs"; perhaps that is what you were thinking of? As Christopher mentioned, stars like our sun will eventually swell to become red giants. (Of course, our own sun doesn't have sufficient mass to become a supernova.)

For another take on using technology to destabilize stars, other than the 2009 movie, check out Diane Duane's "Rihannsu" novels. I can't remember how realistic the science was, though (if it was explained at all).

 

[Kuri]

@Avro Arrow. This is what I read at the wikipedia article...

" After the hydrogen–fusing period of a main-sequence star of low or medium mass ends, such a star will expand to a red giant during which it fuses helium to carbon and oxygen in its core by the triple-alpha process. If a red giant has insufficient mass to generate the core temperatures required to fuse carbon, around 1 billion K, an inert mass of carbon and oxygen will build up at its center. After a star sheds its outer layers and forms a planetary nebula, it will leave behind this core, which is the remnant white dwarf."

It looked to me like the Red Giant stage occurs, then it becomes a White Dwarf (which may or may not go on to become a supernova, dependant on mass). I see now I confused the terms "white dwarf" and "remnant white dwarf". Or is that wrong too!?!?

K.

 

[Christopher]

Space near a stellar body is not a true vacuum, so you could still have a pressure wave.

Yes, of course, but the medium is immensely more diffuse than air, diffuse enough that it can still be considered a vacuum. So while there would technically be a shock wave, it would be inconsequential for the purposes of this specific discussion, i.e. what would happen to a ship or planet. It wouldn't be like the kind of "shock waves" you see in sci-fi, with a ship near the explosion being rocked violently -- or even worse, pushed outward by it (see my comments above about surfers).

But also, we don't know how such an explosion effects things in sub-space. If you go by the movie, the sub-space shock wave can be quite devastating, and travels much faster than the speed of light.

Yes, but that's handwavey gibberish, and Kuri specifically expressed a desire to get the science right.

By the way... is it possible that a white dwarf has enough mass on its own to go supernova without the need for a former binary twin? It can work both ways for me. They just come to the system after the binary is absorbed, if needed.

Again: the other star is not absorbed. Only a portion of its outer atmosphere is absorbed. A white dwarf is just the leftover core of a star that's already blown off most of its mass. It's much, much smaller than an intact star. It's massive and dense enough that, if it's orbiting close enough to a normal star, it can suck up some of that star's outer atmosphere and stellar wind. Remember what I said about TNG: "Evolution." A binary system like this will be a periodic nova star -- the cycle of gas accumulation and fusion explosion will happen repeatedly, since the white dwarf is only sucking up some of the other star's mass. Eventually, it'll escalate to an explosion big enough to rip both stars apart, but they'll both still be there until the explosion happens.

By itself, a white dwarf can never come remotely close to going supernova. Like I said -- a white dwarf is the corpse of a star less than 9 times the mass of the Sun. It's the pit left over after the peach is gone, the small, dense core that remains when the star's outer layers have been expelled. The largest a white dwarf can ever possibly get is 1.4 times the mass of the Sun (if it's the remains of a relatively large star). But a single, non-binary star can only go supernova if it's more than 9 times the mass of the Sun.

For another take on using technology to destabilize stars, other than the 2009 movie, check out Diane Duane's "Rihannsu" novels. I can't remember how realistic the science was, though (if it was explained at all).

It wasn't all that plausible. The idea there was that going to warp near a star would automatically cause it to explode, even if it wasn't a supernova-candidate star. We've seen since then that this doesn't actually happen, although there was one case where a Klingon ship (I think it was Kurn's ship in TNG: "Redemption, Part II") triggered a stellar flare by going to warp just over a star's atmosphere. That's somewhat more plausible.

It looked to me like the Red Giant stage occurs, then it becomes a White Dwarf (which may or may not go on to become a supernova, dependant on mass). I see now I confused the terms "white dwarf" and "remnant white dwarf". Or is that wrong too!?!?

Just two different ways of saying the same thing. A white dwarf is the stellar remnant of a relatively low-mass star. The remnants of higher-mass stars are neutron stars and black holes.


If you really want to write plausibly about astronomy, I'd recommend going to the library and checking out some general books on the subject, or maybe some video series like Cosmos. It's easier to get a handle on specific phenomena like this if you have a grounding in the more general principles of how stars, gravity, light, etc. work.

 

[Vance]

Photon torpedoes aren't as super-deadly as a lot of fiction makes them out to be . With the numbers given, they work out to only about 25MT .. nothing to sniff at on our scale, of course, but really just on the higher-end of the scale of current US nuclear weapons.

And that really isn't going to be much more than a 'poof' when you throw it at a star. In theory, it could be JUST enough to push a start that's already critical and about to go... but it would be impossible to tell.

 

[Kuri]

@Christopher Consider me admonished.

It seems I have picked up the wrong idea from wikipedia re:white dwarfs. Let me, then, reframe the question (and sorry about moving the goalposts)...

Assume we have a [insert type] star that is on the verge of going supernova naturally. This is going to happen of its own accord in, say, 2k, 5k or even 10k years if you like. By human timescale, not even on the horizon (it took longer to go from stone clubs to warp 5), but in cosmic terms "any second now".

How would a Federation starship provide the little "push" to hasten this natural occurance?

It seems to me the most powerful catalyst available is one or more photon torpedoes - it doesn't need to provide the mass or even all the energy, just light the spark that sets off a firework all ready to go.

@Vance - yes something like that.

I like the idea of transporting it into the [insert type] star's core, as it has been mentioned here that that would prove difficult for a transporter (to "push" the object into an area of such dense mass). Could this effort fry the transporter? If I could wreck the transporter room that would be a splendidly useful by-product!

The thought occurs that ensuring detonation in a location of such intense pressures might be a problem - like lighting a match at the bottom of the ocean.

Thank you for your continued patience!

Kuri

 

[Vance]

Well, if you want to 'ignite' such a reaction, you'll want to pour energy into it at a constant high-yield stream. Phasers wouldn't have the yield, but I suppose it's possible that a number of 'anti-borg-deflector-weapons' might pull it off. But, again, we're talking a fairly massive scale here, with nano-percentage differences that would barely register on sensors.

Because a sun is a mass of incandescent gas. A gigantic boiling furnace. With hydrogen converting into helium at a temperate of millions of degrees.

 

[Kuri]

@Vance - there is an alternative (possibly...). When I read up on supernovae, I got the idea that they occur when a star has actually used up its fuel: The constant nuclear reaction before that keeps it at a sort equilibrium, throwing out energy that counterracts the gravitational pressures. When the flame goes out, it implodes, collapsing under its own gravity - then the supernova process immediately follows (the "helium flash").

So imagine the Federation starship lighting a metaphorical match in a sealed environment: The flame eats up the last fragment of oxygen (fuel) then quickly sputters out. Then, BOOM. The problem to me seems to be a star even on the imminent verge of supernova still has oodles of fuel left - far more than a brace of torpedoes can eat up.

And my understanding stemmed from the assumption that white dwarfs were the stage close to just before supernova, so may well be flawed...

Kuri

 

[Christopher]

Assume we have a [insert type] star that is on the verge of going supernova naturally. This is going to happen of its own accord in, say, 2k, 5k or even 10k years if you like. By human timescale, not even on the horizon (it took longer to go from stone clubs to warp 5), but in cosmic terms "any second now".

How would a Federation starship provide the little "push" to hasten this natural occurance?

It seems to me the most powerful catalyst available is one or more photon torpedoes - it doesn't need to provide the mass or even all the energy, just light the spark that sets off a firework all ready to go.

Realistically, I don't think it's possible. A Type II supernova happens when fusion stops in the core of a star. That sounds contradictory, but what happens is that when fusion stops (at the end of a runaway process where elements fuse into ever heavier elements until they reach iron, at which point no further fusion is possible for reasons that are a whole other discussion), the core starts to cool and shrink, and the outer atmosphere collapses on top of it and hits with such force that the rebounding shock wave blows it all apart. So it's something catalyzed by a change that's inherent to the star itself, and it'll happen when it happens. A torpedo would affect it about as much as an amoeba would affect an elephant stampede.

The only thing I can think of that would make a Type II SN happen sooner is if the star's mass increases significantly. The rate at which fusion happens in a star's core is a function of how hot and dense it is, which is a function of how much mass of hydrogen is above it, crushing down on it (since "down" really means "toward the center"). So a bigger star will burn out faster than a smaller one. It's been proposed that if you could remove large quantities of hydrogen from a star by some kind of monumental astroengineering project, you could prolong its life. So, conversely, if you could increase its mass by a large enough amount, you could shorten its life. But you'd pretty much have to drop a whole gas-giant planet into it to make that much difference.

Not to mention that any star big enough to go supernova is going to be too short-lived to be likely to support life-bearing planets. A star of 9 solar masses or above is probably going to have a lifespan of tens of millions of years at most, maybe even just hundreds of thousands if it's big enough. This is something that Star Trek routinely ignores, though, since the biggest, brightest stars tend to be the ones with names, so there are a lot of Trek planets around stars that couldn't reasonably support life, like Rigel and Deneb.

Really, if your goal is to endanger a planet, then a whole supernova is probably thinking too big. It's overkill. Something like an asteroid strike would be more reasonable; asteroids could potentially be aimed at a planet given enough time and/or energy. Heck, even a shuttlecraft or runabout hitting a planet's surface at close to the speed of light could cause an extinction-level event comparable to the asteroid impact that killed the non-avian dinosaurs, since kinetic energy increases as the square of velocity.

 

[Vance]

Yep, strap a hyper-accelerator on a rail-gun that shoots Volkswagens and you're pretty much wiping out whatever's down below.

Hell, worse.. beam some stores of exposed anti-matter down.. that'll do it.

 

[Kuri]

For reference, here is the chapter from wiki:

"Theoretical studies of many supernovae indicate that most are triggered by one of two basic mechanisms: the sudden re-ignition of nuclear fusion in a degenerate star or the sudden gravitational collapse of a massive star's core. In the first instance, a degenerate white dwarf may accumulate sufficient material from a binary companion, either through accretion or via a merger, to raise its core temperature enough to trigger runaway nuclear fusion, completely disrupting the star. In the second case, the core of a massive star may undergo sudden gravitational collapse, releasing gravitational potential energy as a supernova. While some observed supernovae are more complex than these two simplified theories, the astrophysical collapse mechanics have been established and accepted by most astronomers for some time."

The first method, "sudden re-ignition of nuclear fusion in a degenerate star" is the one I'm shooting for. I just need the spark. @Christopher talked about the situation where it gets the push from a binary companion.

But the "degenerate star" link above leads to this definition:

"In astronomy, the term compact star (or compact object) is used to refer collectively to white dwarfs, neutron stars, and black holes."

... leading me to believe a white dwarf is a candidate to be pushed into supernova by the above-mentioned sudden re-ignition.

If not a white dwarf, what does a star on the imminent verge of natural supernova look like? Or is there no such thing? It has to be induced by outside forces (natural or otherwise)?

Kuri

 

[Kuri]

Realistically, I don't think it's possible... A torpedo would affect it about as much as an amoeba would affect an elephant stampede.

Hmmm. That's rather disappointing - but I thank you. This is why I wanted to check it out. I don't see how a single starship could transfer enough hydrogen to make a difference either (elephants and amoeba again).

So, onto the next proposition. My goal is not, in fact, to destroy the planet (this is an unwanted side effect as far as the crew are concerned). I'm heading into spoiler territory now, but ho-hum never mind. The ship is being pursued by an enemy they cannot defeat and cannot evade (and cannot communicate with). They want to "blind" it with the helium flash from a supernova, theoretically causing it to release its grip and allow them to warp away. Another massive energy pulse - bigger than a single ship could produce on its own - could do the trick.

There is a black hole in the neighbourhood. I can write in any other star types or other celestial objects of any required type, too...

So, to quote my Captain, her voice cracking under the pressure, "Suggestions please, Dr. Ch'vo!"


Kuri

 

[Christopher]

For reference, here is the chapter from wiki:

It sounds to me like that Wikipedia passage is just talking about Type Ia supernovae when it talks about a degenerate star and Type II SNs when it talks about gravitational collapse. It's not really a very well-written sentence. Like I said, your best bet is to get some books that cover astronomy and stellar evolution more generally, and get a broader context for understanding the specific things like this.

... leading me to believe a white dwarf is a candidate to be pushed into supernova by the above-mentioned sudden re-ignition.

But only in the situation I've already described, when it's a close binary companion accreting matter.

If not a white dwarf, what does a star on the imminent verge of natural supernova look like? Or is there no such thing? It has to be induced by outside forces (natural or otherwise)?

No. As I said, a Type II supernova is the result of a strictly internal process, when a star more than 9 times the mass of the Sun reaches the end of its fusion cycle. Whereas a Type Ia SN only happens to a white dwarf or neutron star that's accreting matter from a close binary companion, which would count as an outside force. There's no way for it to happen to a solitary white dwarf or neutron star. After all, those are the remnants of stars that have already died.

 

[Kuri]

@Christopher Maybe I need to look into the binary system situation more closely again. That seems a lot more unstable. Maybe one of the periodic standard novas could be induced? The entity in question has been messing with the stars for aeons anyway, as it happens (it's elephant-sized, if you like)...

Kuri - There's hope yet!