Outburst in OH17.7-2.0

International audienceWe present OH 1612 MHz maser observations towards the pre-planetary nebula OH17.7 2.0 taken with the Nançay radio telescope in 2002 2007. A bursting feature at 73 kms-1 grew by a factor of 11 in 740 days in left-hand circular polarization intensity, reaching a maximum in mid-2005. The OH flux density of features at neighbouring velocities exhibited a rise by a factor of 5 7. During the burst, the degree of circular polarization increased from 7 to 83%. The blue-shifted emission showed weak variations of 7 10% in amplitude with the exception of the bluest feature for which the OH flux decreased with the rate of ~4.4 Jy year-1. Very unusual OH outbursts of individual features and remarkable changes in the shape of the maser profile appear to be linked with recent evolutionary changes in the detached shell