The C/O abundance ratio in the planetary nebula IC 2501.

Abstract

The detection of a silicon carbide feature in the infrared spectrum of the planetary nebula IC 2501 suggests that the nebular envelope is carbon rich (Aitken and Roche 1982). The authors have observed IC 2501 with the IUE satellite and have combined these observations with optical measurements in order to analyse the physical conditions and abundances in the nebula. The derived value of the C/O abundance ratio is 1.2, a result which is insensitive to the adopted value of the electron temperature in the nebula.