SIMBAD references

We have obtained high resolution optical spectra of the planetary nebula Hu 1-2 in the wavelength region of 3700Å-10050Å, with the Hamilton Echelle Spectrograph (HES) at Lick Observatory. Diagnostic analysis indicates that the nebular gas can be represented by inhomogeneous shells of electron density N_ε ≃4000-10000cm^–3, and a gas temperature of 12000-18000K. Using the spherically symmetric photoionization model with appropriate abundances, we tried to accommodate the observed physical conditions and high electron temperatures. The chemical composition of the nebula was derived from calculations using a photoionization model which predicts the observed IUE, HES and ISO line intensities; and the composition was then compared to previous determinations. Model analysis confirms the semi-empirically determined abundance derivations carried out in earlier studies. He and N abundances are high, but those of C, O, Ne and S are very low.