The 2008 outburst in the young stellar system Z CMa: the first detection of twin jets

Author(s)

Whelan, E. T.; Dougados, C.; Perrin, M. D.; Bonnefoy, M.; Bains, I.; Redman, M. P.; Ray, T. P.; Bouy, H.; Benisty, M.; Bouvier, J.; Chauvin, G.; Garcia, P. J. V.; Grankvin, K.; Malbet, F.

Abstract

The Z CMa binary is understood to undergo both FU Orionis (FUOR) and EX Orionis (EXOR) type outbursts. While the SE component has been spectroscopically classified as an FUOR, the NW component, a Herbig Be star, is the source of the EXOR outbursts. The system has been identified as the source of a large outflow; however, previous studies have failed to identify the driver. Here, we present adaptive optics assisted [Fe II ] spectro-images which reveal for the first time the presence of two small-scale jets. Observations made using OSIRIS at the Keck Observatory show the Herbig Be star to be the source of the parsec-scale outflow, which within 2' of the source shows signs of wiggling and the FUOR to be driving a ~0'4 jet. The wiggling of the Herbig Be star's jet is evidence for an additional companion which could in fact be generating the EXOR outbursts, the last of which began in 2008. Indeed, the dynamical scale of the wiggling corresponds to a timescale of 4-8 years which is in agreement with the timescale of these outbursts. The spectro-images also show a bow-shock-shaped feature and possible associated knots. The origin of this structure is as of yet unclear. Finally, interesting low velocity structure is also observed. One possibility is that it originates in a wide-angle outflow launched from a circumbinary disk.

Publication year

2010

Publication type

Journal article

Source

Astrophysical Journal Letters, Vol. 720, no. 1 (Sep 2010), p. L119

ISSN

2041-8205

Publisher

Institute of Physics Publishing

Copyright

Copyright © 2010 The American Astronomical Society.

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