EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 438/3 Article
Free access article

Issue A&A
Volume 438, Number 3, August II 2005
Page(s) 889 - 898
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20052685



A&A 438, 889-898 (2005)
DOI: 10.1051/0004-6361:20052685

Water masers in the massive protostar IRAS 20126+4104: ejection and deceleration

L. Moscadelli1, R. Cesaroni2 and M. J. Rioja3

1  INAF, Osservatorio Astronomico di Cagliari, Loc. Poggio dei Pini, strada 54, 09012 Capoterra (Cagliari), Italy
    e-mail: mosca@ca.astro.it
2  INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
3  Observatorio Astronomico Nacional (IGN), Apartado 1143, 28800 Alcalá de Henares (Madrid), Spain

(Received 12 January 2005 / Accepted 29 March 2005 )

Abstract
We report on the first multi-epoch, phase referenced VLBI observations of the H2O maser emission in a high-mass protostar associated with a disk-jet system. The source under study, IRAS 20126+4104, has been extensively investigated in a large variety of tracers, including H2O maser VLBA data acquired by us three years before the present observations. The new findings fully confirm the interpretation proposed in our previous study, namely that the maser spots are expanding from a common origin coincident with the protostar. We also demonstrate that the observed 3-D velocities of the maser spots can be fitted with a model assuming that the spots are moving along the surface of a conical jet, with speed increasing for increasing distance from the cone vertex. We also present the results of single-dish monitoring of the H2O maser spectra in IRAS 20126+4104. These reveal that the peak velocity of some maser lines decreases linearly with time. We speculate that such a deceleration could be due to braking of the shocks from which the maser emission originates, due to mass loading at the shock front or dissipation of the shock energy.


Key words: masers -- ISM: jets and outflows -- ISM: individual objects: IRAS 20126+4104

SIMBAD Objects



© ESO 2005


What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.