A red dwarf?
What about a red dwarf? Might one be dim enough to avoid being seen
by us, at least in the optical range? Proxima Centauri certainly shows the
idea has some merit. It may be the closest known star to us, but it is
hardly the brightest, as are a number of other such red dwarf stars.
Has anyone conducted infrared explorations for such a star near us?
Are there any searches in the old IRAS and ISO and other relevant
data files for such an object?
If Sol's companion is a red dwarf, then there is a slight chance for
any circling planets to have some kind of life.