As an ongoing study of Magellanic Cloud PNe we have obtained UV spectra of 9 PNe in the SMC to measure their carbon abundances. The spectra were acquired with ACS HRC/PR200L and SBC/PR130L. The ACS prisms give a reasonable resolution in the range of 1200–2500 Å to detect C IV, C III], and C II] nebular emission, essential for chemical studies of PNe. The carbon abundances of SMC PNe, together with those of the LMC previously determined with STIS spectroscopy, will allow a comparative study of nebular enrichment and provide a basis for comparison with stellar evolution models at various metallicities.

Detached shells can be identified from their NIR & MIR colours. We use this to identify PPN candidates, including three like IRAS 18455+0448. These are 19178+1206, 18470+0015 & 18123+0511.

We use H$_2$ as a marker to trace the interaction between the older and slower AGB wind and the newer fast wind. Integral field spectroscopy is a tool to probe the interactions of these winds. The measurement of the various line ratios makes it possible to differentiate between the excitation mechanisms. We have obtained $K$-band observations with UIST+IFU at UKIRT and SINFONI at VLT. The UKIRT observations enable us to locate the areas of emission over an area of $\sim 6 \times 3$ arcseconds, whilst SINFONI can provide high resolution sub-arcsecond observations. IRAS 19306+1407 is a B0/1 spectral type post-AGB/Young PN with a bipolar outflow and displays a mixture of shocks and fluorescence. It has emission lines that emanate from an elongated bipolar structure and bright arcs. The combination of H$_2$ and existing polarimetry enables us to analyse the gas and dust around this evolved star.

New results on the time variation of the radial abundance gradients in the galactic disk are presented on the basis of four different samples of planetary nebulae. These comprise both smaller, homogeneous sets of data, and larger but non-homogeneous samples. Four different chemical elements are considered, namely, O, S, Ar, and Ne. Other objects such as open clusters, cepheids and HII regions are also taken into account. Our analyses support our earlier conclusions in the sense that, on the average, the radial abundance gradients have flattened out during the last 6 to 8 Gyr, with important consequences for models of the chemical evolution of the Galaxy.

Accurate emission line fluxes from planetary nebulae (PNe) provide important constraints on the nature of the final phases of stellar evolution. Large, evolved PNe may trace the latest stages of PN evolution, where material from the AGB wind is returned to the interstellar medium. However, the low surface brightness and spatially extended emission of large PNe have made accurate measurements of line fluxes difficult with traditional long-slit spectroscopic techniques. Furthermore, distinguishing these nebulae from H II regions, supernova remnants, or interstellar gas ionized by a hot, evolved stellar core can be challenging. Here, we report on an ongoing survey of large Galactic PNe ($r > 5^\prime$) with the Wisconsin H-Alpha Mapper (WHAM), a Fabry-Perot spectrograph designed to detect faint diffuse optical emission lines with high sensitivity and spectral resolution. Our sample includes newly revealed $H\alpha$ enhancements from the AAO/UKST and WHAM $H\alpha$ surveys of Parker et al. and Haffner et al. We present accurate emission line fluxes of $H\alpha$, [N II]$\lambda$6583, and [O III]$\lambda$5007, and compare our data to other measurements. We use the emission line ratios and kinematics of the ionized gas to assess, or in some cases reassess, the identification of some nebulae.

We have observed the bipolar post-AGB candidate OH 231.8+4.2, using the mid-infrared interferometer MIDI and the infrared camera with the adaptive optics system NACO on the Very Large Telescope. The NACO images at 2.12 and 3.8 $\mu$m show a bipolar outflow and a flared disk or torus. An unresolved core ($<$200 mas in FWHM) is found at the centre of OH 231.8+4.2 in the 3.8 $\mu$m image. This compact source is resolved with the interferometer. The fringes from the four baselines consistently show the presence of a compact circumstellar material with an inner radius of 30–40 mas, which is equivalent to 40–50 AU at 1.3 kpc. This clearly shows that the mid-infrared compact source is not the central star (3 AU) but circumstellar material.

We present total element abundances based upon newly acquired spectrophotometry of a sample of $>$120 Galactic PNe. We continue to explore the use of the near-IR [S III] features to determine S$^{+2}$ abundances and to improve total extrapolated sulfur - a useful metallicity tracer. With this compilation we explore abundance patterns in PNe that reveal signatures of stellar evolution and nucleosynthesis as well as larger-scale galactic chemical evolution.

We present narrow-band images and high resolution long-slit spectra of the compact planetary nebulae M 1-66, He 2-115, K 3-1, K 3-13 and K 3-30, which present evidence of collimated outflows. Our data reveal the internal structure and kinematics of these objects for the first time.

We present a population synthesis calculation to derive the total number of planetary nebulae (PNe) in the Galaxy from single stars and binaries. By combining the most up-to-date literature results regarding galactic and stellar formation and evolution, we determined the total number of PNe with radii $<$0.8 pc deriving from single stars and binaries to be 46 000$\pm$15 000. By using common envelope (CE) calculations and observational results of main sequence binaries, we predict that 5 000$\pm$1 600 post-CE PNe with radii $<$0.8 pc exist in the Galaxy today. We compare these predictions with the observationally-based estimate of 7 200$\pm$1 800 PNe in the Galaxy with radii $<$0.8 pc. This suggests that many single stars do not produce PNe and that 69$\pm$28% of PNe we observe derive from CE interactions on the Asymptotic Giant Branch (AGB).

Using the Cloudy_3D code (Morisset, this conference), we run a set of models to build a catalog of emission line profiles of PNe. The goal is to cover the main morphologies (spherical, ellipsoidal, bipolar, thin or thick shells) and to compute profiles changing the orientation of the nebula, the expansion velocity law (including or not turbulence), the position/size of the aperture. The results is a huge set of profiles and PV-diagrams that can be compared to observations as a help to derive morpho-kinematical properties of real objects.

We developed a new quick pseudo-3D photoionization code based on Cloudy (Ferland et al.) and IDL (RSI) tools. The code is running the 1D photoionization code Cloudy various times, changing at each run the input parameters (e.g. inner radius, density law) according to an angular law describing the morphology of the object. Then a cube is generated by interpolating the outputs of Cloudy. In each cell of the cube, the physical conditions (electron temperature and density, ionic fractions) and the emissivities of lines are determined. Associated tools (VISNEB and VELNEB_3D) are used to rotate the nebula and to compute surface brightness maps and emission line profiles, given a velocity law and taking into account the effect of the thermal broadening and eventually the turbulence. Integrated emission line profiles are computed, given aperture shapes and positions (seeing and instrumental width effects are included). The main advantage of this tool is the short time needed to compute a model (a few tens of minutes).

The extreme carbon star, AFGL 3068, is losing mass at a rate in excess of 10$^{-4}$ M$_{\odot}$ yr$^{-1}$, and has so far been detected only in the infrared because it is hidden by a thick dust photosphere having a color temperature of $\sim$300K. Using the ACS camera on HST, we have imaged AFGL 3068 with broad-band filters at 0.6 and 0.8 $\mu$m and find a thin, apparently continuous spiral arc winding 4 or 5 times around the location of the star, from angular radii of 2 to 10 arcsec. We interpret this as the projection of nested spiral shells such as were predicted to occur when the mass-losing star is a member of a binary system. In this case, the illumination is presumably provided by ambient galactic starlight. Subsequent near-IR observations with the NIRC2 camera on the Keck II telescope using adaptive optics reveal that AFGL 3068 has two components separated by 0.11 arcsec, or 109 AU at a distance of 1 kpc. One very red component is presumably the mass-losing carbon star, while the other component is apparently a much bluer companion. Assuming each component has mass M(M$_{\odot}$), and ignoring the projection of the separation vector, we find the binary period to be 810 M$^{-0.5}$ yrs, strikingly comparable to the 710-yr separation of the shells obtained from the known outflow velocity of 14.7 km s$^{-1}$.

Millimeter and submillimeter interferometry allows to probe the environment around evolved massive stars, where optical and NIR studies might be severely limited by large extinctions due to dusty environments. We present here the morphology and kinematics of the molecular envelope around the red supergiant star VY CMa. We have used the Submillimeter Array (SMA) to map the $^{12}$CO(J=2–1) line and 1.3 mm continuum emissions with an unprecedent resolution of $<$ 2″ or 3000 AU. While the line emission presents a roughly circular shape with a radius of $\sim$ 6000 AU, the velocity structure is markedly different from that of a simple spherically expanding shell. In particular, there is a significant velocity gradient in the East-West direction, confirming the presence of a bipolar outflow.

We present a $K\prime$-band speckle image and $HK$-band polarimetric images of the proto-planetary nebula Frosty Leo obtained using the 6 m SAO telescope and the 8 m Subaru telescope, respectively. Our speckle image revealed clumpy structures in the hourglass-like bipolar nebula. The polarimetric data, for the first time, detected an elongated region with small polarizations and polarization vector alignment on the east side of the central star. We have performed radiative transfer calculations to model the dust shell of Frosty Leo. We found that micron-size grains in the equatorial dense region and small grains in the bipolar lobes are required to explain the total intensity images, the polarization images, and the spectral energy distribution.

We present 0.18$^{\prime\prime}$ resolution mid-infrared images of OH231.8+4.2 using the Gemini South telescope. The images show a bright central core of $\sim$1$^{\prime\prime}$ in size, with extended emissions in the lobes. We find evidence for different chemical composition of the dust in the core and the lobes from the narrow-band images.

The author presents the results of Berkeley-Illinois-Maryland (BIMA) array interferometric observations in the CO $J=1$–0 line toward X Her and EP Aqr, semiregular pulsating stars with a composite CO line profile, and also reports finding a disklike structure in X Her. In the CO spectrum both of X Her and EP Aqr, a composite profile including narrow and broad components is seen as reported by the previous single-dish observations. The spatial structure of the broad component region of X Her shows a bipolar shape, and that of the narrow component shows an elliptical/spherical shape. The blue- and red-shifted parts of the X Her narrow component show a systematic difference in the velocity integrated intensity map. The spatio-kinematic properties of the X Her narrow component are reminiscent of a Keplerian rotating disk with a central mass of 0.9 M$_{\odot}$. The spatial distributions of both the narrow and the broad components of EP Aqr appear to be roughly round with the same peak positions; no significant velocity gradient is seen. The spatio-kinematic properties of EP Aqr are reminiscent of a multiple-shell structure model rather than of a bipolar flow and disk model.

We use UVES spectroscopy of PB 6 to study the variation of its physical conditions as a function of position including: temperature, density, chemical composition and velocity. We present preliminary results from this work. In particular we want to find the relevance of the contribution of the wind from the central star to the chemical composition of the nebula; we find that the contamination due to the WR wind is small.

From VLT FORS1 on-band, off-band imaging of the dIrr NGC3109 we have identified about 13 PN candidates. According to our criteria for PN candidate selection, most of the candidates reported by Richer & McCall (1992) are in fact compact HII regions. Further multi-object VLT FORS1 spectroscopy has confirmed the PN nature of at least 6 candidates. All but one of the PNe analyzed are low excitation nebulae, showing no He II emission lines. For several PNe and HII regions, we derived chemical abundances based on electron temperatures measured from the [O III] 4363/5007 line ratios. Preliminary results show that PNe present log(O/H)+12 in the range from 7.7 to 8.4, while in HII regions this quantity spreads in a much narrower range from 7.6 to 7.8. Thus, the ISM in NGC 3109 seems chemically homogeneous.

We present preliminary conclusions derived from the analysis of a sample of galactic PNe with [WC]-type central stars (WCPNe) observed with Spitzer/IRS. We report the detection of double-dust (C-rich and O-rich) chemistry in all stars in the sample for which a good S/N spectrum was obtained. Our observations reveal that the simultaneous presence of oxygen and carbon-rich dust features in the infrared spectra of WCPNe is not restricted to late/cool [WC]-type stars, as previously suggested in the literature, but it is found to be a common feature associated to all WCPNe. In particular, mixed chemistry is observed in at least seven early/hot WCPNe in the sample. Various scenarios are proposed to interpret the results obtained in the framework of the chemical evolution of PNe.

The discovery of $\sim$500 planetary nebulae (PNe) in the bulge region allows us to probe the bulge out to $\sim8$ kpc. This opens up the possibility to track bulge-disc interactions to unprecedented details. We present an exploration of bulge dynamics with Nbody models of a triaxial bulge embedded in an exponential disc (Peyaud 2005).