Recent optical observations of circumstellar and interstellar phenomena

Complex motions are found over the shells which comprise the Honeycomb nebula. Evidence is presented for an episodic jet from Eta Carinae. The compact globules with radial spokes in the Helix nebula have both been shown to have dusty, molecular cores. Finally, highspeed flows of ionized gas are shown to be associated with the compact knots in the vicinity of the Trapezium cluster in the Orion nebula.     

The origin of the strings in the outer regions of η Carinae

The narrow optical filaments ('strings' or 'spikes') emerging from the Homunculus of η Carinae are modelled as resulting from the passage of ballistic 'bullets' of material through the dense circumstellar environment. In this explanation, the string is the decelerating flow of ablated gas from the bullet. An archive Hubble Space Telescope image and new forbidden-line profiles of the most distinct of the strings are presented and discussed in terms of this simple model.     

Expanding shells within the Helix nebula (NGC 7293)?

Filter photographs and Fabry-Pérot interferograms of the Helix nebula reveal evidence of approximately spherical expansion. Heliocentric radial velocities from +44 to –51 km s^–1 have been detected over the centre of the nebula. A dumb-bell configuration, viewed at a small angle to the longest axis, is proposed to explain many of these observations.     

The Manchester occulting mask imager (MOMI): first results on the environment of P Cygni

The design and first use of the Manchester occulting mask imager (MOMI) is described. This device, when combined with the Cassegrain or Ritchey–Chretien foci of large telescopes, is dedicated to the imagery of faint-line emission regions around bright central sources. Initial observations, with MOMI on the Nordic Optical Telescope (NOT), of the V =4.8 mag P Cygni environment have revealed a ≥5 arcmin long [N  II ] λ6584-Å emitting filament projecting from the outer nebular shell of this luminous blue variable (LBV) star. The presence of a monopolar lobe older than both the inner (22 arcsec diameter) and outer (1.6 arcmin diameter) shells is suggested.