Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-18T09:33:47.868Z Has data issue: false hasContentIssue false

Phase-referenced VLBI observations of the OH masers around U Her

Published online by Cambridge University Press:  25 May 2016

Huib Jan Van Langevelde
Affiliation:
1Joint Institute for VLBI in Europe, Dwingeloo
James Brauher
Affiliation:
2Univ. of Michigan
Philip J. Diamond
Affiliation:
3National Radio Astronomy Observatory, Socorro
Richard T. Schilizzi
Affiliation:
4Joint Institute for VLBI in Europe, Dwingeloo

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We have started phase referenced monitoring of the 1667 MHz masers in the Mira variable U Her. Ultimately we hope to determine the annual parallax for this star. Three sets of VLB A observations have been performed so far. The first on July 22 1994, the second on March 6 1995 and a third on August 14 1995. Observations included bright extragalactic sources to calibrate instrumental effects and cycles of calibrator–source–calibrator (≈ 2° away) of typically 6 minutes. Without any special astrometric analysis software we detect the proper motion of U Her with an accuracy of several milli–arcseconds.

Type
V. From AGB to Planetary Nebulae
Copyright
Copyright © Kluwer 1997 

References

Norris, R.P., Booth, R.S., Diamond, P.J., Nyman, L.A., Graham, D.A., Matveyenko, L.I., 1984, MNRAS 208 435.Google Scholar
Sivagnanam, P., Diamond, P.J., Le Squeren, A.M., Biraud, F., 1990 A &A 229, 171.Google Scholar
Van Langevelde, H.J., Spaans, M., 1993, MNRAS 264, 597.Google Scholar