Long-term polarimetric observations of OH127.8+0.0
  OH 1612 and 1667 MHz masers from the well known object OH127.8+0.0 were mon-
itored in full-polarization mode over a period of 6.5 years and mapped with
MERLIN at one epoch. The OH variability pattern of the star is typical of
extremely long- period AGB stars. The distance determined from the 1612 MHz
light curve and a new measurement of the angular radius is 3.87 (0.28) kpc. At
both frequencies, the flux of polarized emission tightly follows the total flux
variations while, the degrees of circu- lar and linear polarization are
constant within measurement accuracy.. There is net polarization at both lines.
The magnetic field strength estimated from a likely Zeeman pair is -0.6 mG at
the distance of 5400 au from the star.At the near and far sides of the
envelope, the polarization vectors are well aligned implying a regular
structure of the magnetic field. The polarization characteristics of the OH
maser emission suggest a radial magnetic field which is frozen in the stellar
wind.
