VLBA SiO maser observations of the OH/IR star OH 44.8-2.3: magnetic field and morphology
Conference contribution, 2012

We report on Very Long Baseline Array SiO maser observations of the OH/IR star OH 44.8 - 2.3. The observations show that the maser features form a ring located at a distance of 5.4 AU around the central star. The masers show high fractional linear polarization up to 100%. The polarization vectors are consistent with a dipole field morphology. Additionally, we report a tentative detection of circular polarization of 7% for the brightest maser feature. This indicates a magnetic field of 1.5 ± 0.3 G. The SiO masers and the 1612 MHz OH masers suggest a mildly preferred outflow direction in the circumstellar environment of this star. The observed polarization is consistent with magnetic field structures along the preferred outflow direction. This could indicate the possible role of the magnetic fields in shaping the circumstellar environment of this object.

Magnetic Fields





N. Amiri

Leiden University

Wouter Vlemmings

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

A. Kemball

Joint Institute for VLBI in Europe (JIVE)

H. J. van Langevelde

University of Illinois

Proceedings of the International Astronomical Union

1743-9213 (ISSN) 1743-9221 (eISSN)

Vol. 8 S287 54 - 58

Subject Categories

Astronomy, Astrophysics and Cosmology


Basic sciences





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9/6/2018 2