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Six years of astrometric monitoring of the OH maser in U Herculis

Published online by Cambridge University Press:  03 August 2017

Wouter Vlemmings
Affiliation:
Sterrewacht Leiden, Postbus 9513, 2300 RA Leiden, the Netherlands
Huib Jan van Langevelde
Affiliation:
Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo, the Netherlands
Phil Diamond
Affiliation:
Jodrell Bank Observatory, University of Manchester, Macclesfield, Chesire, SK11 9DL, England

Abstract

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Using VLBI phase referencing, we have been registering the position of the most blue-shifted OH 1667 MHz maser spot with respect to nearby extragalactic reference sources for almost seven years. The data for these 10 epochs allow us to determine the proper motion and parallax of U Her. It also yields the opportunity to compare the maser position to the position of the star, as measured by the Hipparcos satellite. Results support the theory that the compact bright spot is the amplified stellar image.

Type
Part 2. Stellar Masers
Copyright
Copyright © Astronomical Society of the Pacific 2002 

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