Is the Galactic Halo Planetary Nebula PN G243-37.1 an ``O VI Sequence'' Variable Object?

Abstract

Archival IUE spectra of the Galactic halo planetary nebula PN G243-37.1 have been reprocessed by the NEWSIPS routine. The new results show a much richer emission-line spectrum than has previously been reported. Several C iii, C iv, O v, and possibly O vi features were detected. P Cygni line profiles could not be identified with certainty. The He ii lambda1640 emission, which is the strongest line in the IUE spectrum and is likely a mixture of stellar and nebular origin, increased in intensity as did the stellar continuum level between observational epochs of 1988 and 1990, which suggests that the object is a variable planetary nebula. A very recent optical spectrum confirms the UV results and suggests that the object underwent a dramatic change, possibly as a result of an episodic mass-loss event.