Magnetic fields around late-type stars using water maser observations

W. H. T. Vlemmings; H. J. van Langevelde; P. J. Diamond

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Magnetic fields around late-type stars using water maser observations

W. H. T. Vlemmings·H. J. van Langevelde·P. J. Diamond

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Abstract

We present the analysis of the circular polarization, due to Zeeman splitting, of the water masers around a sample of late-type stars to determine the magnetic fields in their circumstellar envelopes. The magnetic field strengths in the water maser regions around the Mira variable stars U Ori and U Her are shown to be several Gauss while those of the supergiants S Per, NML Cyg and VY CMa are several hundred mG. We also show that large scale magnetic fields permeate the CSE of an evolved star; the polarization of the water masers around VX Sgr reveals a dipole field structure. We shortly discuss the coupling of the magnetic field with the stellar outflow, as such fields could possibly be the cause of distinctly aspherical mass-loss and the resulting aspherical planetary nebulae.

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W. H. T. Vlemmings, H. J. van Langevelde, P. J. Diamond. 2005-07-11. Magnetic fields around late-type stars using water maser observations. https://arxiv.org/abs/astro-ph/0507258

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