i dunno about this possibly inhabited large object coming to us needing to execute a "burn" at all, but i suspect it may be a "mothership" and the occupants are on a mission to collect a certain "elect" because there is a massive solar event coming up real soon that will extinct the humans and cause these "aliens" who are our ancestors, to lose access to their base genome, which they have been showing up for quite a long time every so often to gather genetic material to bring back into their gene lines.

a 20km diameter roughly spherical spacecraft could contain hundreds of thousands of people inside it, as well as supplies and living facilities.

the one thing that will tell me this is likely is what direction it's coming from. if it's coming from the outer edge of the galactic disc, from the vicinity of the constellation of taurus, then i rate it 90%+ chance that this is how they are going to make their appearance.

the signs of a potential massive solar flare or micronova coming are speeding up a lot faster than was expected.

if their purpose is in maintaining the human genetics to keep their own from degrading then they certainly would not want to let the best of us from being washed away in a pole shift, if we don't get fried by an evil sun...