The Washington Post has reported that KIC 8462852, otherwise known as Tabby's star, in the constellation Cygnus, is a yellow to white dwarf star. As of May, 2017, it is beginning to flicker again, and so a whole host of astronomical instrumentation is being trained on the object again, even you read this. Some detail about this appears also in the Wikipedia article. https://www.washingtonpost.com/vide...bdf918-3fe9-11e7-b29f-f40ffced2ddb_video.html As this is something not generally recognized as a phase of stellar evolution for an F-type main sequence star, this is rather interesting. Some suggestions for why it does this, similar to the ones suggested in the Post article, also appear in the Wikipedia entry: https://en.wikipedia.org/wiki/KIC_8462852 Tabby's star, named for its discoverer Tabitha Boyjian, is one of several known objects with variable luminosity. Some of the other reported objects have actually exhibited both regularity and also deeper dips in luminosity than Tabby's Star. The recent boom in discovery of exoplanets has had the side effect of instrumentation that is much better at finding such objects more quickly and with greater regularity than at any previous period in the history of astronomy. Facilities like SETI have been around for decades and have already sent directed and tightly focused transmissions in other likely directions in the sky relating to the existence of intelligent life on our own planet (although this may be debatable). Even if these transmissions ever reach an alien civilization with the capacity to receive such broadcasts, the range would be very limited, about 10-20 light years, before all of the transmit power we could muster fades into intergalactic background noise. If we were 100% certain of the direction in which we wished to send a transmission, how difficult would it really be to set up the stellar equivalent one of those old style Naval morse code signaling devices to operate point to point? Only one large enough to eclipse a star at the outer reaches of a solar system over a couple of arc seconds would be required. Depending on the technology used and the resources available, possibly this would not be either prohibitively expensive or a drain on the resources of a sufficiently advanced alien civilization. I think this makes more sense than imagining an alien civilization actually building a Dyson sphere. If you can do something like that, would it not be easier to wait until the star cannot support life and simply move the civilizaton to a newer one? Like the Dyson sphere featured and depicted in an episode of STTNG (the one where James Doohan 'Scotty' had landed a shuttle craft on its surface and stored himself and Franklin in a transporter buffer), stars eventually become quite problematic to contain or manage, even under the best of circumstances. Even something like Larry Niven's Ringworld would eventually become a prohibitively costly bridge to nowhere. But using stars themselves for interstellar communication within a sparsely populated region of space bigger than tens or even hundeds of light years would make perfect economic sense. Owing to prohibitive time delays, such communication would likely be half duplex, and we would only be intercepting half of the channel, many aeons after it had been sent, obviously. Most of us would probably agree, this would be both secure and safe enough to be practical.