Proper motions of L1551 IRS 5 binary system using 7 mm VLA observations
  We analyzed high angular resolution observations of the Very Large Array
archive at a wavelength of 7 mm of the L1551 IRS 5 binary system. Six sets of
observations,five with the A configuration and one with the B configuration,
were used, covering a time span of about 15 years. With these multi-epoch data,
we estimated the absolute and relative proper motions of the binary system,
which are about 25.1 mas/yr (~ 16.7 km/s considering a distance of 140 pc) and
4.2 mas/yr, respectively. Finally, based on the relative proper motion, we
estimated a total mass of the L1551 IRS 5 binary system of 1.7 Msun and an
orbital period of 246 years.
