Water Maser Emission Around Low/Intermediate Mass Evolved Stars
Abstract
We present results of Very Long Baseline Array (VLBA) polarimetric 22 GHz H2O maser observations of a number of low/intermediate mass evolved stars. We observed 3 Miras (Ap Lyn, IK Tau and IRC+60370), 1 semi-regular variable (RT Vir) and 1 pPN (OH231.8+4.2). Circular polarization is detected in the H2O maser region of OH231.8+4.2 and we infer a magnetic field of |B||| = ~45 mG. This implies an extrapolated magnetic field of ~2.5 G on the surface of the central star. The preliminary results on RT Vir and IRC+60370 also indicate the first detection of weak H2O maser linear polarization.
- Publication:
-
Cosmic Masers - from OH to H0
- Pub Date:
- July 2012
- DOI:
- 10.1017/S1743921312006680
- Bibcode:
- 2012IAUS..287...79L
- Keywords:
-
- masers;
- magnetic fields;
- polarization;
- stars: AGB and post-AGB