|
|
Paper: |
Phase-lag Distances of OH Masing AGB Stars |
Volume: |
497, Why Galaxies Care about AGB Stars III: A Closer Look in Space and Time |
Page: |
473 |
Authors: |
Engels, D.; Etoka, S.; Gérard, E.; Richards, A. |
Abstract: |
Distances to AGB stars with optically thick circumstellar shells
cannot be determined using optical parallaxes. However, for stars with
OH 1612 MHz maser emission emanating from their circumstellar shells,
distances can be determined by the phase-lag method. This method
combines a linear diameter obtained from a phase-lag measurement with
an angular diameter obtained from interferometry. The phase-lag of the
variable emission from the back and front sides of the shells has been
determined for 20 OH/IR stars in the galactic disk. These measurements
are based on a monitoring program with the Nançay radio telescope
ongoing for more than 6 years. The interferometric observations are
continuing. We estimate that the uncertainties of the distance
determination will be ∼20%. |
|
|
|
|