1995A&A...303L..21A

We present high-resolution 12CO J=1-0 maps of the post-AGB star 89 Her, obtained with the IRAM interferometer at Plateau de Bure. The cartography reveals the presence of two distinct shells. The outer one is very clumpy and placed at distances from the star between 4 and 6x10¹⁶cm (for a distance to 89 Her of 600pc). The inner one has an outer radius of about 10¹⁶cm. It is found that the outer/inner shell emission mainly correspond to the wing/core component of the CO line profile. We deduce an approximate molecular gas mass of 2x10^–4 and 6x10^–5M_sun for the outer and inner circumstellar structures respectively. The CO envelope properties are compared with those derived from previous attempts to model the circumstellar dust emission from 89 Her.