While there are historical reports of a "red" Sirius, those come almost exclusively
from the Mediterranean. Neither Chinese nor American (in both Americas) astronomers
reported it to be red.
Do you know of any documented astronomical reports from the time between Babylonian times and the first century A.D. or so which contradict these red accounts? If so (as the way your writting seems to suggest) where are they from, what year/s have they been dated to; and in what way have they been authenticated?
Hence, it is not clear what the explanation is, but it is most likely
not associated with a nova explosion, nor even a smaller explosion (also, Sirius B is too
cold today for that).
Really; we know that a nova or even a smaller burn-off stage can't be cooled in two thousand years time, how is that possible? You'd think we'd need atleast two thousand years observation under our current level (or near) technology to've fallen under the chance surcumbstances of even observing such a thing in order to form any kind of reasonable conclusion, and even then their would be no ability to ascertain a repetitive consistancy to the reactions involved.
The reports you mention have indeed suggested that, as have a few reports earlier in the
20th century. The last paper by the astronomers you mention, however, concluded that
most probably it is NOT a triple system.
Does this speak anything towards weither or not it could have been thousands of years ago?