So, I was watching various sci channel shows, and they touch on how extremely massive stars live only 100k years, vs the sun which lives ~10 billion years, and dwarf stars live some unspecified time longer.
So, lets say you have a galactic civilation, worried about "heat death", and in order to avoid it, they decide to take apart a number of large stars, making them into a cluster of dwarf stars, so the star will take much longer to burn out...
First, can a group of dwarf stars orbit a common center, close enough that we can considering their combined luminosity as a unit? maybe if we can get them all within the orbital distance of mercury from the common center? Not sure how stable orbits would be once your talking a dozen or more objects?
Second, how much luminosity loss is there? Say you have a combined cluster of 20 dwarf stars, each 1/20 of the mass of the sun, and all within a sphere of mercury's orbit? How much lower would the combined luminosity be -- and so, how much closer would earth have to be in order to maintain liquid water? I'd guess you'd still have some extreme seasons as you made closest approch to any one dwarf.
Third, if we know how close earth would have to get -- could there be a stable orbit around such a cluster, at that range?
Finally, if you can do all that, do you really get much added time? Assuming the source star was halfway thru it's main sequence when split into the cluster of dwarfs, so I guess you'd be estimating the remaining lifetime of a dwarf star (each 1/20 of a stellar mass), which is halfway thru its main sequence?
Edit: Since this is such a multi-stage question: if we know we can refute something right away (ie: perhaps you cannot have a dozen dwarf stars in any stable orbit unless they are very far apart), that could end the issue right away.