Volume 499, Number 2, May IV 2009
|Page(s)||529 - 533|
|Section||Interstellar and circumstellar matter|
|Published online||16 April 2009|
The X-ray emission from Z Canis Majoris during an FUor-like outburst and the detection of its X-ray jet
INAF – Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo, Italy e-mail: email@example.com
2 European Southern Observatory, Casilla 19001, Santiago 19, Chile
3 Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic
4 Observatory and Planetarium of Johann Palisa, VŠB–TU Ostrava, Czech Republic
5 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany
Accepted: 16 March 2009
Accretion shocks have been recognized as an important X-ray emission mechanism for pre-main sequence stars, and yet the X-ray properties of FUor outbursts, events that are caused by violent accretion, have been given little attention. We observed the FUor object Z CMa during optical outburst and quiescence with Chandra. No significant changes in X-ray brightness and spectral shape were found, suggesting that the X-ray emission is coronal. The binary nature of Z CMa makes the origin of the X-ray source ambiguous. However, the moderate hydrogen column density derived from our data makes it unlikely that the embedded primary star is the X-ray source. The secondary star, which is the FUor object, is thus responsible for both the X-ray emission and the ongoing accretion outburst, which seem, however, to be unrelated phenomena. The secondary is also known to drive a large outflow and jet, which we detect here for the first time in X-rays. The distance of the X-ray emitting outflow source to the central star is greater than in jets of low-mass stars.
Key words: X-rays: stars / accretion, accretion disks / stars: pre-main sequence / stars: variables: general / stars: activity / stars: winds, outflows
© ESO, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.