Stellar OH masers and magnetic fields - VLBI observations of U Orionis and IRC +10420

Citations Over TimeTop 15% of 1979 papers

Abstract

This letter reports single-antenna and VLBI interferometric observations of the unusual stellar hydroxyl masers U Ori and IRC +10420. It is found that the apparent sizes of all the maser components from -50 to -40 km/s with flux densities greater than 1 Jy in U Ori have increased by at least an order of magnitude over a three-year period, indicating a change in the physical conditions of the masing region, that the integrated 1612-MHz flux density of U Ori decreased by a factor of four over the same period, and that the emission is partly circularly polarized but less than 5% linearly polarized. An interferometric position for the OH maser in IRC +10420 is determined and shown to agree with the optical position within the errors. Magnetic-field strengths of about 10 mG are estimated for the masing regions of both sources, along with surface magnetic fields of approximately 10 G for U Ori and 100 G for IRC +10420.

Related Papers

• → Mapping Observations of 6.7GHz Methanol Masers with the Japanese VLBI Network(2008)37 cited
• → Use of the Long Baseline Array in Australia for Precise Geodesy and Absolute Astrometry(2009)10 cited
• → First mm-VLBI Observations between the TRAO 14-m and the NRO 45-m Telescopes: Observations of 86 GHz SiO Masers in VY Canis Majoris(2004)7 cited
• → OH maser emission from F- and G-type supergiant stars(1993)1 cited
• → Merlin Observations of the OH Maser Emission from IRC+10420(1984)