Volume 494, Number 3, February II 2009
|Page(s)||1041 - 1051|
|Section||Stellar structure and evolution|
|Published online||22 December 2008|
The enigmatic X-rays from the Herbig star HD 163296: Jet, accretion, or corona?*
Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: email@example.com
Accepted: 26 November 2008
Context. Herbig Ae/Be stars (HAeBe) are pre-main sequence objects in the mass range 2 < < 8 . Their X-ray properties are uncertain and, as yet, unexplained.
Aims. We want to elucidate the X-ray generating mechanism in HAeBes.
Methods. We present an XMM-Newton observation of the HAeBe HD 163296. We analyse the light curve, the broad band and the grating spectra, fit emission measures and abundances and apply models for accretion and wind shocks.
Results. We find three temperature components ranging from 0.2 keV to 2.7 keV. The He-like triplet indicates an X-ray formation region in a low density environment with a weak UV photon field, i.e. above the stellar surface. This makes an origin in an accretion shock unlikely; instead we suggest a shock at the base of the jet for the soft component and a coronal origin for the hot component. A mass outflow of yr-1 is sufficient to power the soft X-rays.
Conclusions. HD 163296 is thought to be single, so this data represent genuine HAeBe X-ray emission. HD 163296 might be prototypical for its class.
Key words: stars: formation / stars: individual: HD 163296 / X-rays: stars / stars: emission-line, Be / 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.