A collision reversal in HD5980

HD 5980 provides a unique laboratory for studying the properties of windwindcollisions. It contains one of only two binary systems having a WRstar in orbitwith a LBV. The latter star has been observed to undergo major changes in itswind structure over the past 35 years, implying changes in the geometry andemitting conditions of the windwind collision region. Ten years ago, when theLBV wind was very strong, XMM observations revealed Xray emission consistentwith the shock cone wrapping around the WR component. Since then, the LBV windstrength has significantly declined, implying that the collision shock cone maybe inverting its orientation. The objective of this proposal is to obtain Xraycoverage of this never before observed phenomenon. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]