THE NEBULAR SPECTRUM OF BD-1.05 MU-M(303639, 0.36)

The dusty young low-excitation planetary nebula ED +30 3639, denoted a s 'Campbell's hydrogen envelope star', has been the subject of many in vestigations, particularly in the infrared wavelength region. We are c oncerned here with a hi,oh-dispersion study of the optical spectrum. D etailed high-spectral-resolution observations of BD + 30 3639 have bee n made at the centre of the nebular image with a slit 1.2 x 4.0 arcsec (2), for the wavelength region 3650 to 10 050 Angstrom, using the Hami lton echelle spectrograph at Lick Observatory. This compact nebula has a density of about 10(4) atoms cm(-3) and T-epsilon similar to 8800 K . Its chemical composition does not seem to be remarkable; it resemble s roughly that of the Sun, although the luminous central star exhibits the spectrum of a classical carbon Wolf-Rayet type with T-eff = 30 00 0 K. It is suggested that the planetary nebula may brighten and rise i n excitation as the central star evolves and grows hotter.