EDP Sciences
Free access
Issue
A&A
Volume 434, Number 1, April IV 2005
Page(s) 213 - 220
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20041872


A&A 434, 213-220 (2005)
DOI: 10.1051/0004-6361:20041872

The masers towards IRAS 20126 + 4104

K. A. Edris1, 2, G. A. Fuller2, R. J. Cohen3 and S. Etoka3

1  Astronomy Dept., Faculty of science, Al-Azhar University, Naser City, Cairo, Egypt
2  School of Physics and Astronomy, University of Manchester, PO Box 88, Manchester, M60 1QD, UK
    e-mail: G.Fuller@manchester.ac.uk
3  University of Manchester, Jodrell Bank Observatory, Macclesfield, Cheshire SK11 9DL, UK

(Received 20 August 2004 / Accepted 22 December 2004)

Abstract
We present MERLIN observations of OH, water and methanol masers towards the young high mass stellar object IRAS  20126+4104. Emission from the 1665-MHz OH, 22-GHz H2O and 6.7-GHz CH3OH masers is detected and all originates very close to the central source. The OH and methanol masers appear to trace part of a circumstellar disk around the central source. The positions and velocities of the OH and CH3OH masers are consistent with Keplerian rotation around a central mass of ~5 $M_\odot$. The water masers are offset from the OH and CH3OH masers and have significantly changed since they were last observed, but still appear to be associated to the outflow from the source. All the OH masers components are circularly polarised, in some cases reaching 100 percent while some OH components also have linear polarisation. We identify one Zeeman pair of OH masers and the splitting of this pair indicates a magnetic field of strength ~11 mG within ~0.5'' (850 AU) of the central source. The OH and CH3OH maser emission suggest that the disk material is dense, n>106 cm-3, and warm, T>125 K and the high abundance of CH3OH required by the maser emission is consistent with the evaporation of the mantles on dust grains in the disk as a result of heating or shocking of the disk material.


Key words: stars: formation -- masers -- ISM: individual objects: IRAS  20126+4104

SIMBAD Objects



© ESO 2005