S Per 1.3 cm Water Masers MERLIN

The water masers are found between 50 and 190 AU from the star. They form about 100 clumps thought to correspond to individual masing clouds. The unbeamed size of these clouds, 15 - 20 AU, has never been measured before. They are distributed in a spherical shell; the ring-like appearance is caused by tangential beaming showing the stellar wind in this region is undergoing acceleration due to radiation pressure on dust grains.
Richards, Cohen(Manchester) and Yates(Herts)

S Per 18 cm OH Masers EVN

In contrast to the water masers the OH masers are brightest at extreme velocities but close to the line of sight to the star; note that the faint striations are instrumental effects. A fainter surrounding ring is clearly resolved for the first time by these VLBI observations. This shows that the OH masers spatially overlap the water maser regions, further evidence for the clumpy nature of the outflow. Preliminary analysis of Zeeman splitting of the OH lines suggests a magnetic field between -450 and 180 nT at various locations in the OH shell between 80 and 180 AU from the star.
Masheder (Bristol/JIVE), van Langevelde (JIVE) Richards and Cohen (Manchester), Greenhill (CfA, Harvard-Smithsonian) and Gray (Bristol)

WR147 6 cm MERLIN

MERLIN images of the X-ray luminous Wolf-Rayet system WR147 reveal thermal radio emission coincident with the WN8 star and associated with its stellar wind. The images also show non--thermal emission along the binary axis and close to the companion B star, about arcsec to the north, detected by both UKIRT and the the HST. The shape of the thermal source around the WN8 star shows that its stellar wind is not spherically symmetric. The non-thermal source is direct evidence for a colliding-wind origin for the emission, with the B star being just luminous enough to provide a wind of sufficient strength.
Williams (ROE) et al. 1997, MNRAS, 289, 10

S140 IRS1 6 cm MERLIN

A MERLIN 6cm map of the thermal emission from the ionized wind of the massive young stellar object S 140 IRS 1; the resolution is 0.1 arcsec. The wind is highly elongated with dimensions of 400x100 AU. The major axis of the wind is actually perpendicular to the outflow from this object as observed via a bipolar CO outflow and near-IR light reflected from the walls of the blue-shifted outflow lobe. This is the best example yet of equatorial mass loss from luminous YSOs which may be due to the presence of an accretion disk feeding the wind or flattening of the wind due to rapid rotation of the young star.
Hoare (Leeds) and co-workers