Th. Neckel

RNO 1B — A New FU Ori in Cassiopeia

GN 00.33.9, on the POSS red print a barely visible nebulosity within the dark cloud L 1287, is now a well defined nebula with cometary shape. The star RNO IB, which is deeply embedded in this nebula (A v ~ 9.2 mag), shares all properties defining a FU Ori: it has brightened by at least 3 mag since 1978, its spectral type is F8I-III with a broad, variable and blueshifted P Cygni profile at Hα and broad, double-peaked absorption lines, including Lil 6707. The star coincides within errors with the cold IRAS source 00338+6312 (L[IRAS] = 440 L⊙), which drives a bipolar CO outflow.

Photometry of comet P/Halley at near post-perihelion phases

Photometric measurements of Halley’s comet at phases around its recent perigee are presented. Narrow band filters isolating C2 Swan band emission and a neighboring continuum, besides the standard UBV, have been used with 4 nucleus centered field stops subtending angles between 41″ and 1050″. The brightness fluctuations detected, especially conspicuous in C2 and the nearby continuum, indicate a period of 7.3 days. Some evidence for the double peaked nature of the periodic variation is marginally present.

Bipolar Nebulae Driven by the Winds of Young Stars

We review the observed properties of young bipolar nebulae. S106 and Cep A are discussed in detail, three recently discovered objects (GN 20.18.3, NS14 and L810) are presented. The characteristics of young bipolar nebulae are then compared to those of young stellar objects (YSOs) observed as cold luminous IRAS sources associated with dense molecular cores and bipolar outflows. It is concluded that they belong to the same early evolutionary stage.

What Causes the Variability of the PV Cep Nebula

We present Gunn r, I, and [SII] images of the variable PV Cep nebula, and longslit spectroscopy taken between 1989 and 1994. The variations in brightness and color are probably due to variable extinction by dust in the wind of PV Cep, implying strong variations of its mass loss rate.

Optical Traces of Two IRAS Sources Driving Bipolar Outflows in the S287 Molecular Cloud

Deep imaging and longslit spectroscopy of two cold, embedded IRAS sources of intermediate luminosity, powering molecular outflows, shows that they are associated with bipolar reflection nebulae. The reflected light consists mainly of H emission with a broad P Cygni profile, as is typical for Herbig Ae/Be stars. The inferred wind velocities are 85 to 120 km s-1.