A model for the 1987 outburst of the recurrent nova U Scorpii

Abstract

U Sco is the recurrent nova with the shortest known recurrence time (8 yr). Therefore, the authors have simulated the outburst of U Sco by accreting material, with a solar abundance of the CNO nuclei, at a rate of 1.1×10-6M_sun;yr-1 onto a 1.35 M_sun; white dwarf. One of the most important results is that it takes this evolutionary sequence only ≡2.6 yr to reach runaway conditions and ultimately eject 4×10-7M_sun; moving with speeds exceeding ≡400 km s-1. A major fraction of the accreted material remains on the surface of the white dwarf so that it must be growing toward the Chandrasekhar limit and will ultimately suffer a supernova explosion.