2009A&A...499..249P

The spectra of the planetary nebula NGC6210 is reanalysed using spectral measurements made in the mid-infrared with the Spitzer Space Telescope and the Infrared Space Observatory. The aim is to determine the chemical composition of this object. We also make use of IUE and ground based spectra. Abundances determined from the mid-infrared lines, which are insensitive to electron temperature, are used as the basis for the determination of the composition, which is found to differ somewhat from earlier results. The abundances found, especially the low value of helium and oxygen, indicate that the central star was originally of rather low mass, probably ≤1M_☉. Abundances of phosphorus, iron, silicon, sodium, potassium and chlorine have been determined, some for the first time in this nebula. The electron temperature in this nebula is constant. The temperature, radius and luminosity of the central star is also discussed. It is shown that the luminosity is consistent with that predicted for a star of 0.9M_☉. But the predicted nebular age is inconsistent with the observed kinetic age.