XMM OBSERVATIONS OF THE DOUBLE DEGENERATE BINARY SYSTEM RXJ0806.3+1527

We propose a followup XMM study of RXJ0806.3+1527, a double degenerate binarysystem with the shortest orbital period known (321 s). Chandra ACISS and XMMobservations carried out in November 2001 and 2002 (simultaneously with VLTobservations) strengthen the above interpretation and allow us to characteriseits soft Xray spectrum (a lowabsorbed blackbody component with kT65eV).However, in both the Chandra and XMM observations we found evidences forspectral features which we identified as Fe XVII and He and Hlike O absorptionedges. The requested XMM observation is mainly aimed at characterising theseabsorption features and searching for additional ones testifying to the presenceof heavy chemical elements. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]