A couple of years ago I read a non-journal paper by Clemant Vidal titled - “Starivore Extraterrestrials? Interacting Binary Stars as Macroscopic Metabolic Systems.,” and recently – this was picked up by Vice Motherboard.
I was curious as to what set of observations could legitimately be carried out to test for Starivores. The concept which seems most approachable might be in sampling spectra of accreting binaries which have an edge-on inclination – like the method used to detect exoplanets via lightcurves.
But instead of generating the lightcurve alone, could you also take spectra while the entire system is facing you and while the majority of the accretion trail is occluded behind the large mass star? Would the rotational period of a binary system like this be long enough that you could expose long enough during the transit?
From undergrad research, I know that hydrogen alpha is used to find CV’s, but I never learned anything about what spectral clues to look for in terms of heavier stuff. I would guess that silicon, lithium, sodium, would have much higher abundance than most metals, and that you would need enough material in the atmosphere to make the absorption line detectable.
So then, assuming that the you are able to deduce the spectra of the accretion stream and disc – could there be any indication as to loss of heavier elements and rotational energy which might result in having artificially controlled flow of the accretion stream?
I would imagine, even if the above observations were possible, you’d still need to repeat this on similar binaries in multiple places. Then you’d need to compare samples, and look for correlation in one spatially proximate area. (Or run back proper motion) Also, I would imagine that CV white dwarf partners are off the table because novas would be a risk to infrastructure. Even controlled accretion flow would eventually hit unstable mass ranges.
Anyway, could an experiment like this actually work? IMO I think we’ll spot ETI’s handiwork well before we get a communication signal. If I were setting up an interstellar internet, directed coherent light between com-points would make a lot more sense than broad reaching radio dealing with R3
Here’s a visual of the experiment I would propose: