Unveil accretion onset mechanisms of a normal outburst of EXO 2030+375

We propose to observe the Be/Xray binary system EXO 2030+375 during itsperiastron passage for 30 ks to study the onset of the accretion activity.Accretion disc instability at the border of the magnetosphere have beenevidenced by quasiperiodic hourlong flux oscillations detected during INTEGRALserendipitous observations in 2011 and by EXOSAT in 1985. Existing RXTEsnapshots observations during past outbursts are unable to characterise the wayin which matter begins to penetrate into the magnetosphere. The unprecedentedsensitivity of XMMNewton and its continuous coverage will allow us toinvestigate in detail the opening of the magnetic gate for this highmagneticfield neutron star. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]