Preparing for the next 'Nova of the Century'

CHANGES IN THE AMOUNT OF MATERIAL REACHING THE ACCRETION DISK BOUNDARY LAYER CAN DRASTICALLY MODIFY ITS STRUCTURE. WE ARE WITNESSING SUCH CHANGES IN A SYMBIOTIC RECURRENT NOVA T CRB FOR THE FIRST TIME. TWO OBSERVATIONS WITH NUSTAR AND XMM HAVE REVEALED THAT THE ACCRETION RATE HAS INCREASED BY A FACTOR OF ABOUT 10 AND THAT THE BOUNDARY LAYER HAS BECOME OPTICALLY THICK. THE NEXT STEP TOWARD OUR UNDERSTANDING OF THE CURRENT STATE IS TO OBSERVE T CRB WHEN IT RETURNS TO ITS QUIESCENCE LEVEL WHICH MAY HAPPEN DURING AO19. THIS TOO OBSERVATION WILL ALLOW US TO TEST THE IDEA THAT NOVA ERUPTIONS IN T CRB FOLLOW AFTER MULTIYEAR PERIODS OF ENHANCED ACCRETION ONTO THE WHITE DWARF DUE TO AN ACCRETION DISK INSTABILITY. IT WILL ALSO HELP US STUDY DISK INSTABILITY EVENTS IN LARGE ACCRETION DISKS.