EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 498/3 Article
Free access article

Issue A&A
Volume 498, Number 3, May II 2009
Page(s) 753 - 759
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361/200811365
Published online 19 March 2009

A&A 498, 753-759 (2009)
DOI: 10.1051/0004-6361/200811365

The extremely collimated bipolar H$_{\sf 2}$O jet from the NGC 1333–IRAS 4B protostar

J.-F. Desmurs1, C. Codella2, J. Santiago-García1, 3, M. Tafalla1, and R. Bachiller1

1  Observatorio Astronómico Nacional (IGN), Alfonso XII 3, 28014 Madrid, Spain
    e-mail: desmurs@oan.es
2  INAF, Istituto di Radioastronomia, Sezione di Firenze, Largo E. Fermi 5, 50125 Firenze, Italy
3  IRAM, Avenida Divina Pastora 7, 18012 Granada, Spain

Received 17 November 2008 / Accepted 5 February 2009

Abstract
Context. We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding medium.
Aims. The main aim is to measure the absolute positions and proper motions of the H2O spots in order to investigate the kinematics of the region from where the jet is launched.
Methods. We imaged the protostars in the nearby region NGC 1333–IRAS 4 in the water maser line at 22.2 GHz by using the VLBA in phase-reference mode at the milliarcsecond scale over four epochs, spaced by one month to measure proper motions.
Results. Two protostars (A2 and B) were detected in a highly variable H2O maser emission, with an active phase shorter than four weeks. The H2O maps allow us to trace the fast jet driven by the B protostar: we observed both the red- and blue-shifted lobes very close to the protostar, $\le$35 AU, moving away with projected velocities of ~10–50 km s-1. The comparison with the molecular outflow observed at larger scale suggests a jet precession with a 18$\arcmin$ yr-1 rate. By measuring the positional spread of the H2O spots we estimate a jet width of ~2 AU at a distance of ~12 AU from the driving protostar.


Key words: stars: formation -- radio lines: ISM -- ISM: jets and outflows -- ISM: molecules -- masers



© ESO 2009


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.