The Halo Planetary Nebulae M 2-29 and BB-1

Abstract

Spectrophotometric data for the two planetary nebulae are given and compared to the data for a well-understood type of planetary nebula (PN) for classification and measurements of abundances. M 2-29 and BB-1 were observed in the wavelength ranges of 3500-5000 and 6000-7500, and the visual calibrated spectra and emission-line fluxes are given along with previous UV data. A reddening correction is applied, and the physical conditions, ionic abundances, and total abundances are presented. Of particular note are the M-2-29 O/H ratio (determined to be the lowest of the planetary nebulae), the high concentrations of C, N, and Ne in BB-1, and the low abundances of Ar and S in BB-1. M 2-29 is theorized to belong to the Type-IV PN group which contains high abundances of Ar and S, and progenitor stars are concluded to be responsible for O and Ne excesses in planetary nebulae.