Cool dwarfs in wide multiple systems. Paper 4: a common-proper-motion
  pair of two identical mid-M dwarfs separated by about 10000 AU
  LSPM J0651+1843 and LSPM J0651+1845 are two high-proper-motion stars recently
claimed to form a binary system, FMR 83, by Rica (2012). Here we characterize
the system in detail, using astrometric and photometric data, and find that the
pair consists of two M4+/-1 dwarfs separated by 9500^(+6200)_(-3800) AU. With
these results, FMR 83 becomes one of the very few 'ultrafragile' systems (i.e.,
systems with very low total masses and very wide physical separations), many of
which have been identified in this series of papers.
