To date, the planetary nebula (PN) survey of the Deep Sky Hunters collaboration has led to the detection of more than 250 previously unknown candidate planetary nebulae (PNe). About 60% of them were found during the past two years and are expected to be true, likely or possible PNe because careful vetting has already thrown out more doubtful objects. The majority of the new PN candidates are located within the boundaries of the SHS and IPHAS Ha surveys and were discovered by combining MIR data from the WideField Infrared Survey Explorer (WISE) with optical data from the IPHAS, SHS and DSS surveys, and UV data from the Galaxy Evolution Explorer(GALEX).

Ou4 is a recently discovered bipolar outflow with a projected size of more than one degree in the plane of the sky. It is apparently centred on the young stellar cluster -whose most massive representative is the triple system HR8119- inside the HII region Sh 2-129. The driving source, the nature, and the distance of Ou4 are not known. Deep narrow-band imagery of the whole nebula at arcsec resolution was obtained to study its morphology. Long-slit spectroscopy of the tips of the bipolar lobes was secured to determine the gas ionization mechanism, physical conditions, and line-of-sight velocities. An estimate of the proper motions at the tip of the south lobe using archival images is attempted. The existing multi-wavelength data for Sh 2-129 and HR 8119 are also comprehensively reviewed. The morphology of Ou4, its emission-line spatial distribution, line flux ratios, and the kinematic modelling adopting a bow-shock parabolic geometry, illustrate the expansion of a shock-excited fast collimated outflow. The radial velocities and reddening are consistent with those of Sh 2-129 and HR 8119. The improved determination of the distance to HR8119 (composed of two B0 V and one B0.5 V stars) and Sh 2-129 is 712 pc. We identify in WISE images a 5 arcmin-radius (1 pc at the distance above) bubble of emission at 22 micron emitted by hot (107 K) dust, located inside the central part of Ou4 and corresponding to several [O III] features of Ou4. The apparent position and the properties studied in this work are consistent with the hypothesis that Ou4 is located inside the Sh 2-129 HII region, suggesting that it was launched some 90 000 yrs ago by HR8119. The outflow total kinetic energy is estimated to be ~4e47~ergs. However, the alternate possibility that Ou4 is a bipolar planetary nebula, or the result of an eruptive event on a massive AGB or post-AGB star not yet identified, cannot be ruled out.

Several [WC]-type central stars of planetary nebulae (PNe) are known to mimic the spectroscopic appearance of massive carbon-rich or WC-type Wolf-Rayet stars. In stark contrast, no [WN]-type central stars have yet been identified as clear-cut analogues of the common nitrogen-rich or WN-type Wolf-Rayet stars. We have identified the [WN3] central star of IC 4663 to be the first unambiguous example in PNe. The low luminosity nucleus and an asymptotic giant branch (AGB) halo surrounding the main nebula prove the bona-fide PN nature of IC 4663. Model atmosphere analysis reveals the [WN3] star to have an exotic chemical composition of helium (95%), hydrogen (<2%), nitrogen (0.8%), neon (0.2%) and oxygen (0.05%) by mass. Such an extreme helium-dominated composition cannot be predicted by current evolutionary scenarios for hydrogen deficient [WC]-type central stars. Only with the discovery of IC 4663 and its unusual composition can we now connect [WN] central stars to the 0(He) central stars in a second H-deficient and He-rich evolutionary sequence, [WN]-> O(He), that exists in parallel to the carbon-rich [WC]-> PG1159 sequence. This suggests a simpler mechanism, perhaps a binary merger, can better explain H-deficiency in PNe and potentially other H-deficient/He-rich stars. In this respect IC 4663 is the best supported case for a possible merged binary central star of a PN.

Abell 70 (PN G038.1−25.4, hereafter A 70) is a planetary nebula known for its diamond ring appearance due to a superposition with a background galaxy. The previously unstudied central star is found to be a binary consisting of a G8IV–V secondary at optical wavelengths and a hot white dwarf at ultraviolet wavelengths. The secondary shows Ba II and Sr II features enhanced for its spectral type that, combined with the chromospheric Hα emission and possible 20– 30 km s −1 radial velocity amplitude, firmly classifies the binary as a Barium star. The proposed origin of Barium stars is intimately linked to planetary nebulae (PNe) whereby wind accretion pollutes the companion with dredged-up material rich in carbon and s-process elements when the primary is experiencing thermal pulses on the asymptotic giant branch (AGB). A 70 provides further evidence for this scenario together with the other very few examples of Barium central stars. The nebula is found to have Type I chemical abundances with helium and nitrogen enrichment, which when combined with future abundance studies of the central star, will establish A 70 as a unique laboratory for studying s-process AGB nucleosynthesis. We also discuss guidelines to discover more binary central stars with cool secondaries in large orbits that are needed to balance our knowledge of binarity in PNe against the currently better studied post-common-envelope binary central stars.

Over the last decade Galactic planetary nebula discoveries have entered a golden age due to the emergence of high sensitivity, high resolution narrow-band surveys of the Galactic plane. These have been coupled with access to complimentary, deep, multi-wavelength surveys across near-IR, mid-IR and radio regimes in particular from both ground-based and space-based telescopes. These have provided powerful diagnostic and discovery capabilities. In this review these advances are put in the context of what has gone before, what we are uncovering now and through the window of opportunity that awaits in the future. The astrophysical potential of this brief but key phase of late stage stellar evolution is finally being realised.

AbstractWe have found the central star of Abell 70 (PN G038.1–25.4, hereafter A 70) to be a binary consisting of a G8 IV-V secondary and a hot white dwarf. The secondary shows enhanced Ba II and Sr II features, firmly classifying it as a barium star. The nebula is found to have Type-I chemical abundances with helium and nitrogen enrichment, which combined with future abundance studies of the central star, will establish A 70 as a unique laboratory for studying s-process AGB nucleosynthesis.

Since the issue of the unifying Strasbourg-ESO Catalogue of Galactic Planetary Nebulae (SECGPN) a large number of new discoveries have been made thanks to improved surveys and discovery techniques. The increasingly heterogeneous published population of Galactic PNe, that we have determined totals < 2850 PNe, is becoming more difficult to study on the whole without a centralised repository. We introduce a consolidated and interactive online database with object classifications that reflect the latest multi-wavelength data and the most recent results. The extensible database, hosted by the Centre de Donnees astronomique de Strasbourg (CDS), will contain a wealth of observed data for large, well-defined samples of PNe including coordinates, multi-wavelength images, spectroscopy, line intensities, radial velocities and central star information. It is anticipated that the database will be publicly released early 2012.

We present the discovery of 6 nebular objects made by amateur astronomers. Four of these discoveries are clearly planetary nebulae (PNe), one is a. possible PN, and another is a likely H II region. The bipolar nebula Ou4 presents the largest angular extent; ever found: over one degree on the sky! We consider various scenarios that could explain such a nebula. Ou4 could be one of the nearest PNe known, though its possible PN nature will need confirmation.

We present spectra of 32 previously unpublished confirmed and candidate Wolf-Rayet ([WR]) and weak emission-line (WELS) central stars of planetary nebulae (CSPNe). Eighteen stars have been discovered in the Macquarie/AAO/Strasbourg H-Alpha (MASH) PN survey sample, and we have also uncovered 14 confirmed and candidate [WR]s and WELS among the CSPNe of previously known PNe. Spectral classifications have been undertaken using both the Acker & Neiner and Crowther, De Marco & Barlow schemes. Twenty-two members in this sample are identified as probable [WR]s; the remaining 10 appear to be WELS. Observations undertaken as part of the MASH spectroscopic survey have now increased the number of known [WR]s by ~30 per cent. This will permit a better analysis of [WR] subclass distribution, metallicity effects, and evolutionary sequences in these uncommon objects.

The central star of the planetary nebula (CSPN) M 2-29 shows an extraordinary R Coronae Borealis-like fading event in its optical lightcurve. The only other CSPN to show these events are CPD-568032 (Hen 3-1333) and V651 Mon (NGC 2346). Dust cloud formation in the line of sight appears responsible but the exact triggering mechanism is not well understood. Understanding how planetary nebulae (PNe) trigger dust obscuration events may help understand the same process in a wide range of objects including Population-I WC9 stars, symbiotic stars and perhaps Asymptotic Giant Branch (AGB) stars with long secondary periods (LSPs). A binary scenario involving an eccentric, wide companion that triggers dust formation via interaction at periastron is a potential explanation that has been suggested for LSP variables. Model fits to the lightcurves of CPD-568032 and M 2-29 show the dust forms in excess of 70 AU at the inner edge of a dust disk. In the case of CPD-568032 this radius is far too large to coincide with a binary companion trigger, although a binary may have been responsible for the formation of the dust disk. We find no direct evidence to support previous claims of binarity in M 2-29 either from the OGLE lightcurve or deep medium-resolution VLT FLAMES spectroscopy of the CSPN. We classify the CSPN as Of(H) with T_eff=50+-10 kK and log g=4.0+-0.3. We find a mean distance of 7.4+-1.8 kpc to M 2-29 at which the M_V=-0.9 mag CSPN could potentially hide a subgiant luminosity or fainter companion. A companion would help explain the multiple similarities with D'-type symbiotic stars whose outer nebulae are thought to be bona-fide PNe. The 7.4 kpc distance, oxygen abundance of 8.3 dex and Galactic coordinates (l=4.0, b=-3.0) prove that M 2-29 is a Galactic Bulge PN and not a Halo PN as commonly misconceived.

AbstractRecent Hα surveys such as SHS and IPHAS have improved the completeness of the Galactic planetary nebula (PN) census. We now know of ∼3000 PNe in the Galaxy, but this is far short of most estimates, typically ~25 000 or more for the total population. The size of the Galactic PN population is required to derive an accurate estimate of the chemical enrichment rates of nitrogen, carbon, and helium. In addition, a high PN count (>20 000) is strong evidence that most main-sequence stars of mass 1–8 M⊙ will go through a PN phase, while a low count (<10 000) argues that special conditions (e.g. close binary interactions) are required to form a PN. We describe a technique for finding hundreds more PNe using the existing data collections of the digital sky surveys, thereby improving the census of Galactic PNe.

Planetary nebulae (PN) are powerful tracers of both stellar and Galactic evolution. The capacity of PN to perform these studies is critically dependent on the size of the population, a major problem with a remarkable advance thanks to Quentin Parker and his team, who from 1997 to 2008 discovered an unprecedented sample of ∼1250 PN with the deep, high resolution AAO/UKST SuperCosmos Halpha Survey (SHS) of the Southern Galactic Plane (Parker et al. 2005), doubling the sample collected over the previous century, and leading to ∼2700 for the number of known PN today. A highly productive collaboration between Quentin and I has been established since 2001. Our complementary levels of expertise and facilities constitute the Macquarie/AAO/Strasbourg H-α Planetary Nebulae Project.The new MASH PN were added to the Centre de Données de Strasbourg as a new PN database continuously updated, and detailed in Parker et al. (2006) and Miszalski et al. (2008). In the framework of a cotutelle agreement between the Strasbourg and Macquarie universities, two PhD projects based on MASH PN have been conducted under the supervision of Quentin and myself, both projects focusing on the mysterious crowded region of the Galactic Bulge. Alan Peyaud proposed new constraints on late stages of stellar evolution and on the dynamics of the Galactic Bulge (defence 21 December 2005, Strasbourg). Brent Miszalski discovered ∼360 new PN (MASH-II) completing the largest and most representative sample of PN towards the Galactic bulge (defence 15 August 2009).

Binarity has been hypothesised to play an important, if not ubiquitous, role in the formation of planetary nebulae (PNe). Yet there remains a severe paucity of known binary central stars required to test the binary hypothesis and to place strong constraints on the physics of the common-envelope (CE) phase of binary stellar evolution. Large photometric surveys offer an unrivalled opportunity to efficiently discover many binary central stars. We have combined photometry from the OGLE microlensing survey with the largest sample of PNe towards the Galactic bulge to systematically search for new binaries. A total of 21 periodic binaries were found thereby more than doubling the known sample. The orbital period distribution was found to be best described by CE population synthesis models when no correlation between primary and secondary masses is assumed for the initial mass ratio distribution. A comparison with post-CE white dwarf binaries indicates both distributions are representative of the true post-CE period distribution with most binaries exhibiting periods less than one day. A close binary fraction of 12-21% is derived and is the first robust and independent validation of the previous 10-15% estimate. This suggests that binarity is not a precondition for the formation of PNe and that close binaries do not play a dominant role in the shaping of nebular morphologies. Systematic effects and biases of the survey are discussed with implications for future photometric surveys.

Context. Variability is a key factor for understanding the nature of the most massive stars, the OB stars. Such stars lie closest to the unstable upper limit of star formation.Aims. In terms of statistics, the data from the HIPPARCOS satellite are unique because of time coverage and uniformity. They are ideal to study variability in this large, uniform sample of OB stars.Methods. We used statistical techniques to determine an independant threshold of variability corresponding to our sample of OB stars, and then applied an automatic algorithm to search for periods in the data of stars that are located above this threshold. We separated the sample stars into 4 main categories of variability: 3 intrinsic and 1 extrinsic. The intrinsic categories are: OB main sequence stars (similar to 2/3 of the sample), OBe stars (similar to 10%) and OB Supergiant stars (similar to 1/4). The extrinsic category refers to eclipsing binaries.Results. We classified about 30% of the whole sample as variable, although the fraction depends on magnitude level due to instrumental limitations. OBe stars tend to be much more variable (approximate to 80%) than the average sample star, while OBMS stars are below average and OBSG stars are average. Types of variables include alpha Cyg, beta Cep, slowly pulsating stars and other types from the general catalog of variable stars. As for eclipsing binaries, there are relatively more contact than detached systems among the OBMS and OBe stars, and about equal numbers among OBSG stars.

The history of this magic instrument is complex, and the teaching goal was never forgotten. Technological developments of the planetarium enable it now to treat the major topics of astronomy anti astrophysics. But by simplifying too much or badly, one is likely to bring confusion in the spirits. The development of the planetarium is a continual challenge, as long as the scientific culture is not integrated perfectly in the cultural landscape. In several countries, planetariums link their knowledge and their know-how, for better resisting to economic difficulties, and better speaking about astronomy to their public. In particular the great project ALMA will be celebrated in a. show for the International Year of Astronomy. Today's planetarium works as a theater for all sciences, and can issue a. passport to the various scales of the universe

Considerable effort has been applied towards understanding the precise shaping mechanisms responsible for the diverse range of morphologies exhibited by planetary nebulae (PNe). At least 10–20% of PNe have central stars (CSPN) with a close binary companion thought responsible for heavily shaping the ejected PN during common-envelope (CE) evolution, however morphological studies of the few available examples found no clear distinction between PNe and post-CE PNe. The discovery of several new binary central stars (CSPN) from the OGLE-III photometric variability survey has significantly increased the number of post-CE PNe available for morphological analysis to 30 PNe. High quality Gemini South narrow-band images are presented for most of the OGLE sample, while some previously known post-CE PNe are reanalysed with images from the literature. Nearly 30% of nebulae have canonical bipolar morphologies, however this could be as high as 60% once inclination effects are incorporated with the aid of geometric models. This is the strongest observational evidence yet linking CE evolution to bipolar morphologies. A higher than average proportion of the sample shows low-ionisation knots, filaments or jets suggesting they have a binary origin. These features are also common in nebulae around emission-line nuclei which may be explained by speculative binary formation scenarios for H-deficient CSPN.

The AAO/UKST Hα survey of the Southern Galactic Plane has produced large numbers of new planetary nebulae (PN). These are contained in the Macquarie/AAO/Strasbourg Hα catalogue (MASH) and a supplementary catalogue called MASH-II. The large combined sample of ∼1200 PN offers many new central stars (CSPN) for study. We outline a small portion of these CSPN that have been observed spectroscopically with particular focus on Wolf-Rayet CSPN, of which we find and classify around 30 new objects.