Nançay 1612 MHz monitoring of OH/IR stars



These pages document the progress of an OH 1612 MHz maser monitoring program with the Nançay Radio Telescope started in 2008. Two samples of OH/IR stars are/were monitored, one showing flux variations with periods of several years and large amplitudes (L-AGB sample), and the other with small amplitudes and unknown periodicity (S-pAGB sample). For each OH/IR star a sample maser spectrum and the lightcurve based on the integrated flux is shown. If available, OH 1667 MHz sample spectra are also shown.

Last observation implemented: 2016 August

The large amplitude variable OH/IR stars (L-AGB)
The stars are red giants evolving on the Asymptotic Giant Branch (AGB). The maser emission varies with typical periods of 1 to ~6 years. The lightcurves are used to predict the next maxima of the variations of the OH maser emission. Optimum conditions for mapping the distribution of maser emission is given during these epochs.

List of 1612 MHz OH maser interferometric observations

The small amplitude variable OH/IR stars (S-pAGB)
The stars are red giants, which possibly have left the AGB already and are evolving towards the Planetary Nebula stage. They are candidate post-AGB stars. The study of their variability properties is used to understand the transition process from the AGB to the post-AGB stage, which last probably only a few hundred years. Observations of the first sample (S-pAGB 1) were made 2013 - 2014. For several objects the monitoring is extended until end of 2016. Observations of the second sample (S-pAGB 2) started in 2015.

Collaborators: D. Engels, S. Etoka, E. Gérard, N. Hallet, and A.M.S. Richards

Publications:

Links:



Last modification: Wednesday, 22-Nov-2017 15:00:00 CET | D. Engels