Your ignorance is showing here.
Not just ignorance of - actually, to be fair, limited acquaintance with - the subject under discussion, but your ignorance of the backgrounds, training, professions and hobbies of those you are conducting discussions with.
As it happens, I just finished reading a paper [http://arxiv.org/pdf/1512.01164.pdf] reporting the results of a new code - called SPICE - that models the interaction of stellar winds and the surrounding medium. The paper studies models in the specific context of Type Ia SNe, but the models are broadly applicable and in fact are being used to study influences on things such as galactic evolution. Extrapolating a bit from what was presented, while the grand clash of stellar systems you so eloquently present _can_ happen, it is restricted to the very small percentage of stars in luminosity classes I-III, plus the handful of even more extreme objects like WR stars and LBVs. These are the only stars with the potential to produce winds dense enough to affect their environments over interstellar distances - and some of them can indeed have a reach of >100ly - but whether they actually do so depends on a lot of factors, including age, mass, composition and evolutionary stage. And, of course, precisely what the environment is in the first place. High-mass stars can actually produce smaller effects than you would expect, because they evolve so fast that they are effectively stuck inside their birth environments, which are pretty much by definition high-density, and they move through the dense-wind phases fast enough that the wind can't travel very far before it starts decelerating. Class V stars, even massive ones, produce low-density winds that simply don't dominate the environment over long distances. For ~1-3Msol, modeling and direct observation [Voyager] show a reach of 70-95au; an O3V star might have a wind extending ~2-300au [again, this is a question of phase length rather than potential power - they simply don't spend enough time on the main sequence for it to matter] while the distances for <<1Msol are much less than 70au. IOW, 2 or more MS stars will encounter a colliding-wind scenario only within the confines of a multi-star system. Where annihilating one of them will have immediate and drastic dynamical effects on the system [setting aside the direct effects; see below].
So, since the vast majority of stars in the universe are not going to generate significant effects on each other at typical stellar separations, I think it's safe to ignore them. Let's look at what actually happens if you do get a clash of titans. We'll look at a pair of roughly identical RGB stars, since I happen to have some useful numbers. [HB & AGB stars have different structures, and therefore somewhat different winds] For other combinations, the following has to be scaled up or down or sideways, as appropriate. Assume that they are towards the upper end of their class, so that isolated they would dominate a region 25-30ly across, and that they are separated by 15ly. For the particular, rather arbitrary, scenario I just pick, the contact discontinuities will interact over a region several ly in diameter. Making a conservative estimate, since I can't solve the relevant model here, the density of the medium in that region will be doubled, raising it to a whopping 1.4/cubic centimeter. Uh, that's in units of particles, BTW, not mass. Centre of the zone will be 7.5ly from each star, and the edges ~11.5ly. Take one of those stars away, and no one in the other system would even notice the difference. Well, aside from the second-brightest star in their sky vanishing, of course. A couple of hundred thousand years later there ought to be a change in the local 21cm radio flux, and probably far-infrared emission. Doubt if there will be any other detectable changes.
Even restricting consideration to the RGB, the range at which you can get measurable effects could vary from 2ly to 60ly depending on the specific characteristics of each star. If you consider all possible combinations, the range goes from ~40au to ~150ly. Perhaps you now have an inkling of why I was wondering how, exactly, we should understand "neighbour".
As for annihilation, in physics the term does have a rather narrow meaning: the interaction of a particle with its anti-particle, which neither of them survives. So to me the "total annihilation" of a star requires colliding it with enough antimatter that every electron, neutron and proton in the star annihilates. The result of doing that in a binary system is going to be, to put it mildly, extreme. Do it 150ly away, and most people will be looking for extra sunscreen, although that does depend on how and, especially, how fast you carry out the operation. Nothing involving the mere mechanical disruption of a star is going to be as drastic, although the effects could be far more exciting visually. Simply disappearing it will net you a "that's odd! where did 163 Puppis go? it was right here 3 years ago."
Since the effects in neighbouring systems thus depend not only on where they are but on what is being done to the disappearing star and how efficiently the technique is applied, a certain degree of precision is, at the very least, going to be of great assistance in formulating a response.
cthia wrote:Louis R wrote:There you go with the inaccurate terminology again.
What, precisely, do you mean by total annihilation? And how are you using "neighboring"?
Broadly speaking, you'd get something in the range from "didn't there used to be a star there?" to "bother! pass the sunscreen, please."
Keep it up long enough, and after you've disappeared the first couple of billion nearest neighbours you start to notice some minor dynamical effects. Of course, people would be getting kind of curious by then, and might wander over to ask just what you're up to.
*RIF -- at least keep up with the thread before you attack.
Recent research has yielded that solar winds of opposing solar systems are in a battle to the death. The region between these neighboring solar systems trap particles. Most of which has recently been determined to be hydrogen -- huge bands of hydrogen deposits. (Natural gas stations for Honorverse ships to top off their tanks.)
*Total annihilation of solar systems advances the premise of certain Sci-Fy tech in this thread. So I don't know where you're going with that. And in running with that tech as a gedanken, total annihilation of a solar system -- its sun and the planets that orbit it -- and along with it, the significant change of its influence on its neighboring system, what effect might it have?
Also, total annihilation means that the destruction of the sun and planets is beyond the ability of any remains to accrete. There are no remains.
I went through this already. Perhaps we need a sticky note of the definition of...
an·ni·hi·late
VERB
1.destroy utterly; obliterate
You should also keep abreast of the latest research in cosmology. It seems the idea that two solar systems can neighbor each other is tripping you up. The long arm of the law (gravitational law) has this MO.