2011A&A...532A.149A


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.07CEST17:26:26

2011A&A...532A.149A - Astronomy and Astrophysics, volume 532A, 149-149 (2011/8-1)

The kinematics and magnetic fields in water-fountain sources based on OH maser observations.

AMIRI N., VLEMMINGS W. and VAN LANGEVELDE H.J.

Abstract (from CDS):

water-fountain sources are a class of post-AGB objects that exhibit bipolar jet-like structures traced by H2O maser emission. The circumstellar envelopes of these objects show deviations from spherical symmetry. While the H2O masers originate in a collimated outflow in the polar region, the OH masers may be distributed in the equatorial region or a biconical outflow in the circumstellar shell. Magnetic fields could play an important role in collimating the jet and shaping the circumstellar envelope of these objects. The aim of this project is to understand the morphology of the OH masers in three water-fountain sources, for which we obtained high-resolution interferometric data. We compare the observational parameters of the spectral profile and spatial distribution with our models in order to constrain the morphology and velocity fields of the OH maser shell. We would also like to understand the role of the magnetic field in shaping the circumstellar envelope of these stars. We observed the OH masers of three water-fountain sources (OH 12.8-0.9, OH 37.1-0.8, and W43A) in full polarization spectral line mode using the UK Multi-Element Radio Linked Interferometer Network. Additionally, we performed reconstruction models of OH maser shells distributed uniformly in equatorial or biconical outflows and compared them with the OH maser observations.The OH masers of W43A seem to be located in the equatorial region of the circumstellar shell, while for OH 12.8-0.9 the masers are likely distributed in a biconical outflow. We measured magnetic fields of ∼360µG and ∼29µG on average for OH 37.1-0.8 and OH 12.8-0.9, respectively. The measured field strengths show that a large-scale magnetic field is present in the circumstellar environment of these stars. Our observations show that the OH maser region of the three water-fountain sources studied in this work show signs of aspherical expansion. Reconstruction of the OH maser distribution of these objects show both biconical and equatorial distributions. Magnetic fields likely play an important role in shaping the OH maser region of water-fountain sources.

Abstract Copyright:

Journal keyword(s): stars: individual: W43A - magnetic fields - polarization - masers - stars: individual: OH 12.8-0.9 - stars: individual: OH 37.1-0.8

CDS comments: Paragraph 4.2.2 IRAS 18316-1816 is a probable misprit for IRAS 18139-1816. Tables 1 and 2 maser features not in Simbad

Simbad objects: 12

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Number of rows : 12

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 3C 84 Sy2 03 19 48.1597607660 +41 30 42.114155434   13.10 12.48 11.09   ~ 3551 3
2 3C 286 Sy1 13 31 08.2885060664 +30 30 32.960825108   17.51 17.25     ~ 3736 1
3 IRAS 16342-3814 pA* 16 37 39.8700524769 -38 20 17.440442399           ~ 128 0
4 OH 9.097 -0.392 OH* 18 07 20.861 -21 16 10.86           ~ 33 0
5 OH 12.8 -0.9 IR 18 16 49.214 -18 15 01.66           ~ 45 2
6 IRAS 18139-1816 mul 18 16 51.1 -18 15 02           ~ 16 1
7 QSO J1832-2039 BLL 18 32 11.0447839878 -20 39 48.202176867   18.56 20.2     ~ 38 1
8 OH 31.0 +0.0 OH* 18 47 41.13768 -01 45 11.4048           ~ 125 1
9 OH 37.1 -0.8 OH* 19 02 06.286 +03 20 15.99           ~ 65 0
10 IRAS 18596+0315 mul 19 02 06.4 +03 20 15           ~ 59 1
11 ICRF J190711.9+012708 QSO 19 07 11.9988607394 +01 27 09.018074966           ~ 30 1
12 IRAS 19134+2131 pA* 19 15 35.2088301392 +21 36 33.815011564           ~ 60 0

    Equat.    Gal    SGal    Ecl

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2020.08.07-17:26:26

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