The Collective UV Behavior of Old Novae

Abstract

The UV spectral properties of 18 old-novae observed with IUE are examined. The de-reddened continuum energy distribution is well described by either a power-law distribution F_λ ∼λ ^-α with α in the range 0.3--2.5 or by a single black-body distribution with T in the range 15 000--38 000 K. The new values of E_B-V have led to new estimates of the distances and of the UV luminosities. A tight correlation exists between L_UV and M_V min, and both these quantities show a definite correlation with the system inclination angle cos i. With the assumption that L_UV comes from an accretion disk, one obtains that the ``average" L disk is about 20 L<sub>⊙</sub> and that the ``average" accretion rate ˙ {M} is close to 1 ×10^-8M_⊙ yr^-1, a disturbingly high value.