tokens: the 7 Be ii doublet cannot be resolved, its total equivalent widths, W ( 7 Be ii )s, in the LVC and the HVC are measured. After subtracting the combined effects of contaminations discussed above we tabulate the resulting W ( 7 Be ii ) in Table 3 . The errors of W are estimated from the S/N of the neighboring continuum. They do not include the uncertainties in the continuum placements. Table 3 Equivalent Widths of Blue-shifted Absorption Lines in Observed Novae The abundances of 7 Be in nova ejecta is estimated following the same procedure as used in Tajitsu et al. ( 2015 ). We compare the equivalent widths of Ca ii K () and 7 Be ii (, respectively) in the LVC, which show a simpler structure than the HVC. Here we need the following assumptions: (1) both the 7 Be ii and Ca ii lines are not saturated and (2) the covering factor of the absorbing gas cloud to the background illuminating source has no wavelength dependence. We notice that the LVC feature of 7 Be ii at −786 km s −1 of V5668 Sgr might be saturated. The bottom of the 7 Be ii lines in the LVC almost reaches to that in the HVC where its flat profile suggests that the absorption is saturated. The corresponding LVC component of the Ca ii K line in V5668 Sgr is shallow and the line appears to be unsaturated. The abundance of 7 Be in V5668 Sgr obtained under such a condition should be taken as a lower limit. Following Spitzer ( 1998 , Equations (3)–(48)), the ratio of column number densities, N , can be written asUsing data of the W ( 7 Be ii ) and the listed in Table 3 the column density ratios N ( 7 Be ii )/ N (Ca ii ) derived in the LVC of V5668 Sgr and V2944 Oph are 8.1 ± 2.0 and 2.5 ± 1.5, respectively. These ratios are close to that found in V339 Del at +47 days. The ionization states of each species are keys to convert the above ratios into atomic abundances. We assume that the most of 7 Be is in the singly ionized state because it still stays in hot ejecta. We also assume that Ca is in the singly ionized state. The absence of Ca i lines in the blueshifted absorption line systems supports this assumption. The difference in the second ionization potential (Be: 18.21 eV, Ca: 11.87 eV) may lead to different balances between the second and the third ionized ions and this may be a source of an error in determining the abundances. We tried but failed to detect absorption lines of doubly ionized ions of Fe-peak elements, which have intermediate second ionization potentials, consulting Kramida et al. ( 2014 ). Absorption lines of Fe iii are observed in optical range spectra of B-type stars (Thompson et al. 2008 ). This may support the assumption that all of 7 Be and Ca contained in the LVC are in the singly ionized state. Adopting this assumption, the mass fraction of 7 Be to the sum of all constituent mass components, ( 7 Be ii ), can be presented as: ( 7 Be) ∼ N ( 7 Be ii )/ N (Ca ii ) × 7/40 × X (Ca). We have obtained ( 7 Be)/ (Ca) = 1.4 ± 0.3 for V5668 Sgr and 0.44 ± 0.26 for V2944 Oph.
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