The wind of ksi Per: a tomographic view of stellar wind dynamics

We propose to obtain 11 STIS and 10 XMM spectra of ksi Per to provide thecritical information needed to progress our understanding of the structure of Ostar winds. The details of structures and interactions of the wind are needed toreliably translate observational diagnostics into physical quantities such asmass loss rates which are controversial. The proposed set of combined HST andXMM observations will provide conclusive proof of whether the discreteabsorption components observed in UV wind line profiles are related to Xrayvariability and they will provide the phase difference between the two, whichdetermines their relative locations in the winds. The window of opportunity toobtain such an important and unique data set is closing. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]