| Description |
Carbon (and nitrogen) abundances, which can be used to constrain stellar evolution theory, are not well known in Galactic bulge planetary nebulae because the lines used are in the ultraviolet and are weak and difficult to measure accurately. We propose to measure the C(+) abundance in a selection of low ionization PNe where it is the dominant ion, by measuring the CII line at 157 microns. The nitrogen line at 122 microns is used in conjunction with the line at 6584 angstroms to accurately determine the electron temperature, which not only will make the nitrogen abundance more accurate, but will enable abundances to be determined for other ions measured in the visual spectrum. |
