MERLIN observations of OH/IR stars

Michael Lindqvist, F. L. Schoier, Hans Olofsson, Anita M.S. Richards
2009 Proceedings of The 9th European VLBI Network Symposium on The role of VLBI in the Golden Age for Radio Astronomy and EVN Users Meeting — PoS(IX EVN Symposium)   unpublished
We present MERLIN OH 1612 MHz observations towards 3 OH/IR stars, OH15.7+0.8, OH38.3+1.9 and IRAS 19319+2214. The main objective of the project is to investigate if their complicated OH 1612 MHz spectral properties can be related to the phenomenon of highly timevariable mass loss found towards a handful of carbon stars, where detached shells with an overall spherical symmetry are present. Despite extensive searches, no oxygen-rich star with such a shell has been found in any molecular emission.
more » ... Based on the MERLIN data however, we find that the circumstellar structure of the three OH/IR stars appears to be more complicated than that of detached shells. Signs of bipolarity in the outflows of OH38.3+1.9 and IRAS 19319+2214 could indicate that these are early post-AGB objects. MERLIN observations of OH/IR stars M. Lindqvist Figure 1: The integrated OH 1612 MHz spectrum (middle) and velocity channel maps (left; blueshifted and right; redshifted part of the line profile) towards OH15.7+0.8.
doi:10.22323/1.072.0081 fatcat:ceb4mxm2gjhcdojhi6aoe6z2ri