Interacting jets from binary protostars

¹ Laboratoire d'Astrophysique de Grenoble, CNRS, Université Joseph Fourier, BP 53, 38041 Grenoble, France e-mail: Gareth.Murphy@obs.ujf-grenoble.fr
² European Science Foundation, 1 quai Lezay-Marnesia, BP 90015, 67080 Strasbourg, France e-mail: tlery@esf.org
³ UCD School of Mathematical Sciences, University College Dublin, Belfield, Dublin 4, Ireland e-mail: stephen.osullivan@ucd.ie
⁴ NASA/GSFC Laboratory for Solar and Space Physics, Mail Stop 612.1, Greenbelt, MD 20771, USA e-mail: daniel.s.spicer@nasa.gov
⁵ INAF – Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Florence, Italy e-mail: fran@arcetri.astro.it
⁶ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: arosen@mpifr-bonn.mpg.de

Received: 4 September 2007
Accepted: 13 November 2007

Abstract

Aims. We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems.

Methods. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps.

Results. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet.

Conclusions. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology.
If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets.