PENA, M; TORRESPEIMBERT, S; RUIZ, MT
(1991)
Optical spectrophotometric data are presented for the Population II planetary nebulae (PN) M 2-29 and BB-1. For M 2-29 we derived T(e) (O III) = 24,000 K N(e) (S II) = 3000 cm-3, and chemical abundance of 12 + log He/H = ...