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... more
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. Based on observations made with Gemini South under programs GS-2008B-Q-65 and GS-2009A-Q-35.
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We report infrared observations of the planetary nebula Hen 2-113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and TIMMI at the ESO 3.6m. Hen 2-113 exhibits a clear ring-like structure superimposed to a more diffuse environment visible in... more
We report infrared observations of the planetary nebula Hen 2-113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and TIMMI at the ESO 3.6m. Hen 2-113 exhibits a clear ring-like structure superimposed to a more diffuse environment visible in the L' (3.8μm), M' (4.78μm) and 8.7μm bands. No clear core at 8.7μm and no fringes through the N band could be detected for this object with MIDI. A qualitative interpretation of the object structure is proposed using a diabolo-like geometrical model. Our ISAAC and TIMMI observations indicates that the PAHs are mostly concentrated towards the lobes of the diabolo and the bipolar lobes of the nebula. In L' band, a void 0.3" in diameter was discovered with NACO around the central source, which appears resolved with measured FWHM about 155 mas. Our measurements indicate that the observed fluxes from this source in L' and M' are about 300 and 800 times respectively smaller than those expected from a model including only the central star. This infrared excess can be explained by emission from a cocoon of hot dust (T˜1000K) with a total mass ˜10-9M⊙.
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The table lists the heliocentric radial velocities for planetary nebulae in the direction of the Galactic bulge. The accuracy is about 2km/s. The measurements were made in June and July 1993, using the ESO CAT with spectral resolution of... more
The table lists the heliocentric radial velocities for planetary nebulae in the direction of the Galactic bulge. The accuracy is about 2km/s. The measurements were made in June and July 1993, using the ESO CAT with spectral resolution of 30000-60000. Hα, [NII] 6548 and 6584 and [O III] 5007 were observed. (1 data file).
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The radial velocity curve of FG Sge is established with 80 radial velocities measured from 1977 to 1979 using the spectrophotometer CORAVEL. The mean period is 120 plus or minus 10 days, the mean amplitude and velocity being solar radii,... more
The radial velocity curve of FG Sge is established with 80 radial velocities measured from 1977 to 1979 using the spectrophotometer CORAVEL. The mean period is 120 plus or minus 10 days, the mean amplitude and velocity being solar radii, 3.0 plus or minus 0.2 km/s and 37.5 plus or minus 0.1 km/s. The comparison with the simultaneous photometric variations shows that the luminosity variation happens nearly in phase with the radius variation. Using Wesselink's method, the value of the radius is estimated to about 140 solar radii, which leads to a pulsation mass of about 1 solar mass and a distance of about 2.5 Kpc. The mean broadening of the lines, deduced from the width of the correlation dip of FG Sge, would require a low rotation velocity.
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We compare the populations of Red Giant stars and Planetary Nebulae in the Galactic Bulge, in the light of recent determinations of their abundances patterns. We find both populations to be compatible. From the planetary nebulae, we find... more
We compare the populations of Red Giant stars and Planetary Nebulae in the Galactic Bulge, in the light of recent determinations of their abundances patterns. We find both populations to be compatible. From the planetary nebulae, we find evidences that the Bulge did not form stars recently. The whole abundances pattern remains however puzzling, some elements favoring a quick evolution of the Galactic Bulge (Mg and Ti), and others a much slower one (He, O, Si, S, Ar and Ca).
A planetarium show highlighting the ALMA project is being jointly prepared by ESO and the Association des Planétariums de Langue Française.
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ABSTRACT We report discovery of ~500 planetary nebulae (PNe) in the central 200 sq.deg of the Galactic Bulge from the AAO/UKST Halpha survey. Confirmatory UKST 6dF fibre spectroscopy and additional follow-up on 2-m class telescopes has... more
ABSTRACT We report discovery of ~500 planetary nebulae (PNe) in the central 200 sq.deg of the Galactic Bulge from the AAO/UKST Halpha survey. Confirmatory UKST 6dF fibre spectroscopy and additional follow-up on 2-m class telescopes has led to a doubling of known Bulge PNe. This new population will have important implications for the bulge PN luminosity function and will provide improved determination of abundance gradients, a better picture of chemical evolution, as well as valuable test particles for dynamical studies.
... E. Lagadec, O. Chesneau, M. Matsuura, O. De Marco, JA de Freitas Pacheco, AA Zijlstra, A. Acker, GC Clayton. Abstract. We report infrared observations of the planetary nebula Hen 2‐113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and... more
... E. Lagadec, O. Chesneau, M. Matsuura, O. De Marco, JA de Freitas Pacheco, AA Zijlstra, A. Acker, GC Clayton. Abstract. We report infrared observations of the planetary nebula Hen 2‐113 obtained with VLT/NACO, VLTI/MIDI, VLT/ISAAC and TIMMI at the ESO 3.6m. Hen 2‐113 ...
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The table lists the heliocentric radial velocities for planetary nebulae in the direction of the Galactic bulge. The accuracy is about 2km/s. The measurements were made in June and July 1993, using the ESO CAT with spectral resolution of... more
The table lists the heliocentric radial velocities for planetary nebulae in the direction of the Galactic bulge. The accuracy is about 2km/s. The measurements were made in June and July 1993, using the ESO CAT with spectral resolution of 30000-60000. Halpha, [NII] 6548 and 6584 and [O III] 5007 were observed. (1 data file).
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The exploitation of data from the Halpha southern survey and from the spectroscopic survey of newly discovered planetary nebulae (PN) is focussed on the 1500 PN of the galactic bulge, with the following objectives: -- history of expansion... more
The exploitation of data from the Halpha southern survey and from the spectroscopic survey of newly discovered planetary nebulae (PN) is focussed on the 1500 PN of the galactic bulge, with the following objectives: -- history of expansion linked to the evolutive models as a function of progenitor mass; -- spatial distribution and kinematics to constrain the dynamics.
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PN are excellent tracers for Galactic bulge dynamical studies because they are less affected by metallicity bias than other tracers and have strong emission lines permitting accurate velocity determinations. Due to the relatively small... more
PN are excellent tracers for Galactic bulge dynamical studies because they are less affected by metallicity bias than other tracers and have strong emission lines permitting accurate velocity determinations. Due to the relatively small numbers previously known throughout the Galaxy (i.e. ~1500) compared to those expected ~20000+) their potential as tracers of galactic structure and as windows to stellar evolution in the critical phase between PN and White Dwarf has only been partially realized. Furthermore, the number of bulge PN available for such studies has, until now, also been quite small (e.g. Zijlstra et al. 1997 and Beaulieu et al. 1999) so their potential as test particles of bulge dynamics and PN evolution also remains largely unrealised. We present our new PNe sample and an axisymmetrical model of the Bulge that we will be able to constrain.
Coordinates for 288 planetary nebulae searched for photometric variations in OGLE-III. Remarks are given according to the central star (CSPN) identification process detailed in the paper. For each planetary nebula the OGLE-III field, PN G... more
Coordinates for 288 planetary nebulae searched for photometric variations in OGLE-III. Remarks are given according to the central star (CSPN) identification process detailed in the paper. For each planetary nebula the OGLE-III field, PN G designation, common name, equatorial coordinates and central star ID are given. (1 data file).
The Macquarie/AAO/Strasbourg Halpha Planetary Nebula Catalogue (MASH) contains 903 new true, likely and possible Galactic Planetary Nebulae (PNe) discovered from the AAO/UKST Halpha survey of the southern Galactic plane. The combination... more
The Macquarie/AAO/Strasbourg Halpha Planetary Nebula Catalogue (MASH) contains 903 new true, likely and possible Galactic Planetary Nebulae (PNe) discovered from the AAO/UKST Halpha survey of the southern Galactic plane. The combination of depth, resolution, uniformity, and areal coverage of the H {alpha}survey has opened up an hitherto unexplored region of parameter space permitting the detection of this significant new PN sample. This catalogue includes also the spectra of the PNe as FITS files (in the "sp" subdirectory), and a gallery of images created as a combination of the Halpha and short red images of the survey. The second part, MASH-II (table mash2.dat) consists of over 300 true, likely and possible new Galactic PNe found after re-examination of the entire AAO/UKST Halpha survey of the Southern Galactic Plane in digital form. Over 240 of these new candidates were confirmed as bona fide PNe on the basis of spectroscopic observations. The spectra of this supplement...
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Detection of close binary central stars with periods of less than a day is now well-tested and routinely possible via photometric monitoring. For wide binary central stars with periods of weeks to years detection techniques are still in... more
Detection of close binary central stars with periods of less than a day is now well-tested and routinely possible via photometric monitoring. For wide binary central stars with periods of weeks to years detection techniques are still in their infancy. Radial velocity monitoring programs are yet to be applied to very large samples and the method suffers from large systematic errors as well as intrinsic wind variability. One alternative we are exploring is the detection of dense circumstellar nebulae residing around a wide companion. The archetype of this class is EGB6 as revealed by HST imaging (Bond 2009). Here we present spectroscopic evidence for other EGB6-like central stars and discuss their relationship to symbiotic stars. A probable 12.5-day irradiated binary is also presented to demonstrate the limits of the photometric monitoring technique.
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In the past decade, the Deep Sky Hunters Collaboration has identified more than 200 planetary nebula (PN) candidates by scanning the Digitized Sky Survey (DSS) and other publicly available digital resources (SDSS, GALEX, WISE) mostly... more
In the past decade, the Deep Sky Hunters Collaboration has identified more than 200 planetary nebula (PN) candidates by scanning the Digitized Sky Survey (DSS) and other publicly available digital resources (SDSS, GALEX, WISE) mostly outside the sky regions covered by the SHS and IPHAS surveys. Amongst these 200 objects, we have identified thus far 106 true, probable and possible PNe, increasing the number of known Galactic PNe in the surveyed fields by about 30%. This contribution presents H-alpha and [OIII] images of 37 new PNe and candidates that have been identified during the past three years with the survey technique mentioned above.
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ABSTRACT The AAO/UKST Hα survey is revealing a substantial new population of Planetary Nebulae (PNe) over the southern Galactic Plane including ∼ 550 in the Bulge. Such objects are excellent tracers for Bulge dynamical studies, are less... more
ABSTRACT The AAO/UKST Hα survey is revealing a substantial new population of Planetary Nebulae (PNe) over the southern Galactic Plane including ∼ 550 in the Bulge. Such objects are excellent tracers for Bulge dynamical studies, are less affected by metallicity bias and have strong emission lines facilitating accurate velocities. We present preliminary results on plans to exploit these significant new Bulge PNe. Until now the relatively small numbers previously known has limited their potential as tracers of galactic structure and as windows to stellar evolution in the critical phase between PNe and White Dwarf (e.g. Zijlstra et al. 1997; Durand et al. 1996, 1998; Beaulieu et al. 1999).
We present the Advanced Robotic Agile Observatory (ARAGO), a project for a large variability survey of the sky, in the range 10-8Hz (year) to 1Hz. Among its scientific objectives are the detection of cosmic gamma-ray bursts, both on alert... more
We present the Advanced Robotic Agile Observatory (ARAGO), a project for a large variability survey of the sky, in the range 10-8Hz (year) to 1Hz. Among its scientific objectives are the detection of cosmic gamma-ray bursts, both on alert and serendipitously, orphan afterglows, extrasolar planets, AGNs, quasar microlensing, variable and flare stars, trans-neptunian asteroids, Earth-grazers, orbital debris, etc. A large
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ABSTRACT We present new Galactic Bulge Planetary Nebulae (PNe) revealed by the latest techniques of point-spread function matching (Bond at al. 2001) applied to SuperCOSMOS data of paired H-alpha/SR survey Bulge fields (known as... more
ABSTRACT We present new Galactic Bulge Planetary Nebulae (PNe) revealed by the latest techniques of point-spread function matching (Bond at al. 2001) applied to SuperCOSMOS data of paired H-alpha/SR survey Bulge fields (known as difference imaging). This technique provides cleaner cancellation of normal stars by being able to account for spatially varying psf's in the highly crowded Bulge fields (compared to quotient imaging used previously (Peyaud 2001)). The identification from candidate to true PNe via spectroscopy was performed at SAAO/1.9m and at the UKST/6df telescopes. Until now the number of Bulge PNe available has been modest (
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We report on new photometric, CORAVEL and spectroscopic observations carried out between 1988 and 1991 of the visible G5III central star HD 112313 of the planetary nebula LoTr5 which each of them confirm variability. The power spectrum of... more
We report on new photometric, CORAVEL and spectroscopic observations carried out between 1988 and 1991 of the visible G5III central star HD 112313 of the planetary nebula LoTr5 which each of them confirm variability. The power spectrum of our photometric data collected in March 1989 is similar to those of previous observers but cannot help to decide the true period(s). Radial-velocity measurements of the Halpha_ absorption line obtained in May 1990, January 1991 and April 1991 seem to have a pattern of power spectra similar to photometry. CORAVEL radial-velocity measurements of HD 112313 are of poor quality due to a very wide correlation dip with poor contrast, origin of which should be the high rotational velocity of the G-star (v.sini~70km/s) and possible drastic changes in the spectrum within the course of some hours. The radial-velocity variations of the iron lines shown by CORAVEL are irregular and no stable period appears among five yearly observing runs (about seven days each one), though the pattern of power spectra for June 1988 and July 1989 is also similar to the photometric one.
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We discuss a sample of 101 planetary nebulae (PNe) analyzed with the Torun model. We compare the characteristics of [WR] and wels (weak emission line stars) PNe with those with non-emission line central stars.
We present a compilation of radial velocities for 867 galactic planetary nebulae (Table 2.ps [postscript format] and Table2.dat [ascii format]). (1 data file).
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Observations of planetary nebulae performed with the image dissecting scanner (IDS) of the 1.52-m telescope at La Silla are discussed. The quality of the IDS data is analyzed with attention given to reliability, measurement of blends, and... more
Observations of planetary nebulae performed with the image dissecting scanner (IDS) of the 1.52-m telescope at La Silla are discussed. The quality of the IDS data is analyzed with attention given to reliability, measurement of blends, and the nonlinearity of the IDS system. Misclassified planetary nebulae are identified and some physical properties of planetary nebulae are determined.
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We present high spatial resolution observations of the dusty core of the Planetary Nebula with Wolf-Rayet central star CPD-568032. These observations were taken with the mid-infrared interferometer VLTI/MIDI in imaging mode providing a... more
We present high spatial resolution observations of the dusty core of the Planetary Nebula with Wolf-Rayet central star CPD-568032. These observations were taken with the mid-infrared interferometer VLTI/MIDI in imaging mode providing a typical 300 mas resolution and in interferometric mode using UT2-UT3 47m baseline providing a typical spatial resolution of 20 mas. The visible HST images exhibit a complex multilobal geometry dominated by faint lobes. The farthest structures are located at 7" from the star. The mid-IR environment of CPD-568032 is dominated by a compact source, barely resolved by a single UT telescope in a 8.7 micron filter. The infrared core is almost fully resolved with the three 40-45m projected baselines ranging from -5 to 51 degree but smooth oscillating fringes at low level have been detected in spectrally dispersed visibilities. This clear signal is interpreted in terms of a ring structure which would define the bright inner rim of the equatorial disk. Geometric models allowed us to derive the main geometrical parameters of the disk. For instance, a reasonably good fit is reached with an achromatic and elliptical truncated Gaussian with a radius of 97+/-11 AU, an inclination of 28+/-7 degree and a PA for the major axis at 345+/-7 degree. Furthermore, we performed some radiative transfer modeling aimed at further constraining the geometry and mass content of the disk, by taking into account the MIDI dispersed visibilities, spectra, and the large aperture SED of the source. These models show that the disk is mostly optically thin in the N band and highly flared.
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We report on new photometric and spectroscopic observations carried out in 1989 and 1990 of the visible central star LW Hya = BD-22 3467 deg of the planetary nebula Abell 35. The period of P = 0.766 days we have already found in 1986 and... more
We report on new photometric and spectroscopic observations carried out in 1989 and 1990 of the visible central star LW Hya = BD-22 3467 deg of the planetary nebula Abell 35. The period of P = 0.766 days we have already found in 1986 and 1987 (Jasniewicz and Acker, 1988) is confirmed by the 1990 photometric data, but no photometric variations were found in the 1989 observing run. A second periodicity not yet very well established seems probable (4.2 or 1.9 yr). In addition we have detected emission cores in the H and K Ca II lines: they also vary in intensity both on short and long-term intervals of time. Nevertheless, the short-term variations of Ca II are poorly related to the short photometric period (0.766 d) but seem to be somewhat in antiphase. New spectroscopic observations will be necessary to estimate correctly the long period of the Ca II emission variations. We can thus conclude that a chromospheric activity develops probably at the surface of the subgiant G8 component of the binary system, on the basis of the presence of Ca II emission line cores and on the presence of dark spots deduced by us previously (Acker and Jasniewicz, 1990) to explain brightness variations.
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We present a compilation of radial velocities for 867 galactic planetary nebulae (Table 2.ps [postscript format] and Table2.dat [ascii format]). (1 data file).
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Research Interests: Stellar Evolution, Statistical Analysis, Monte Carlo, Dust (Astronomy & Astrophysics), Standard Deviation, and 10 moreStandard Model, Milky Way, Galactic bulge, Luminosity function, Statistical Properties, Fill Factor, Error Propagation, Physical Properties, Mass Distribution, and Monte Carlo Method
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Using low resolution IDS spectra, an attempt is made to clarify the classification of 264 objects which appeared as planetary nebulae in various listings, and were originally included in two lists of Sanduleak (1976): (1) misclassified or... more
Using low resolution IDS spectra, an attempt is made to clarify the classification of 264 objects which appeared as planetary nebulae in various listings, and were originally included in two lists of Sanduleak (1976): (1) misclassified or doubtfully classified planetary nebulae; and (2) faint, suspected planetary nebulae. The new data show that 67 percent of the objects can be considered as true planetary nebulae, of which 46 percent present low excitation characteristics. The status of the other objects remains quite uncertain, some of them being symbiotic stars (14 percent), or various emission-line objects. In four cases, no positive indication of emission-line objects in the observed areas was found.
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A comparison of the planetary nebulae as derived from the Balmer decrement and from the ratio of radio and H-beta fluxes is presented on the basis of a compilation of all the relevant radio and optical measurements and a serious selection... more
A comparison of the planetary nebulae as derived from the Balmer decrement and from the ratio of radio and H-beta fluxes is presented on the basis of a compilation of all the relevant radio and optical measurements and a serious selection of the best data. It is shown that the extinction determined from the Balmer decrement is systematically larger than the one derived from the radio data, the slope of the (Copt, Crad) relation being about 1.2. It is argued that, for most distant planetary nebulae, the total to selection extinction is significantly lower than 3, the value corresponding to the standard extinction law for the interstellar medium.