Discovery of X-ray emission from the proto-stellar jet L1551 IRS5 (HH 154)

Favata, F., Fridlund, C. V. M., Micela, G., Sciortino, S., and Kaas, A. A.
Stellar Coronae in the Chandra and XMM-NEWTON Era, ASP Conference Proceedings, Vol. 277. Edited by Fabio Favata and Jeremy J. Drake. ISBN: 1-58381-119-2. San Francisco: Astronomical Society of the Pacific, 2002., p.467


We have for the first time detected X-ray emission associated with a proto-stellar jet, on the jet emanating from L1551 IRS5. The IRS5 proto-star is hidden beyond a very large absorbing column density, making the direct observation of the jet's emission possible. The observed X-ray emission is likely associated with the shock ``working surface'', i.e. the interface between the jet and the circumstellar medium. The X-ray luminosity emanating from the jet is moderate, at LX ~ 3 times 10^29 erg/s, a significant fraction of the luminosity normally associated with the coronal emission from young stars. The spectrum of the X-ray emission is compatible with thermal emission from a hot plasma, with T ~ 0.5 MK, fully compatible with the temperature expected (on the basis of the jet's velocity) for the shock front produced by the jet hitting the circumstellar medium.