The 1990 outburst of the recurrent nova V3890 Sgr observed with IUE.

V3890 Sgr (Nova Sgr 1962) is one of the more recent examples of recurrent novae. Its second recorded outbursts took place in April 1990. IUE observations were obtained during the first month after the outburst. The UV spectra show the development of very broad emission lines with complex and variable profiles. Of particular interest is the "narrow core plus broad wings" structure shown by most of the emission lines, and the presence of very high ionization lines (e.g. [Fe XI] 2648 Å). The estimation of the reddening and the distance allows to conclude that the system most probably reached a super-Eddington luminosity in the early phases of the outburst. This is a strong argument in favour of the thermonuclear origin of the outburst.