- ID:
- ivo://CDS.VizieR/J/A+A/403/659
- Title:
- Classification of WR planetary nebulae
- Short Name:
- J/A+A/403/659
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse 42 emission-line nuclei of Planetary Nebulae (PNe), in the framework of a large spectrophotometric survey of [WC] nuclei of PNe conducted since 1994, using low/medium resolution spectra obtained at ESO and at OHP. We construct a grid of selected line-intensities (normalized to C IV-5806{AA}=100) ordered by decreasing ionisation potential going from 871 to 24eV. In this grid, the stars appear to belong clearly to prominent O (hot [WO1-4] types) or C (cooler [WC4-11] types) line-sequences, in agreement with the classification of massive WR stars applied to Central Stars of Planetary Nebulae (CSPNe) by Crowther et al. (1998MNRAS.296..367C, CMB98). We propose 20 selected line ratios and the FWHM of CIV and CIII lines as classification diagnostics, which agree well with the 7 line ratios and the FWHM proposed by CMB98.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/80/211
- Title:
- Compact Radio Sources Near the Galactic Plane
- Short Name:
- J/ApJS/80/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the extension of the 20-cm Galactic-plane survey reported by Zoonematkermani to Galactic latitudes of +/-1.8{deg} over the central region of the Milky Way are reported. A total of 1457 discrete radio sources down to flux densities of less than about 5mJy, and 95% completion is achieved at 20mJy. A detailed comparison of all radio sources from the survey in this longitude range with the IRAS Point Source Catalog provides classification for 13% of the objects, including 159 compact H II regions, and nearly 100 planetary nebulae, over 70 of which are identified. The identity of the remaining radio sources is discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/373/521
- Title:
- Complete catalog of planetary nebulae in LMC
- Short Name:
- J/MNRAS/373/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents accurate homogeneous positions, velocities and other pertinent properties for 460 newly discovered and 169 previously known planetary nebulae (PNe) in the central 25-deg^2^ bar region of the Large Magellanic Cloud (LMC). Candidate emission sources were discovered using a deep, high-resolution H{alpha} map of the LMC obtained by median stacking a dozen 2h H{alpha} exposures taken with the UK Schmidt Telescope (UKST). Our spectroscopic follow-up of more than 2000 compact (i.e. <20arcsec) H{alpha} emission candidates uncovered has tripled the number of PNe in this area. All of the 169 previously known PNe within this region have also been independently recovered and included in this paper to create a homogeneous data set. Of the newly discovered PNe, we classify 291 as 'true', 54 as 'likely' and 115 as 'possible' based on the strength of photometric and spectroscopic evidence. Radial velocities have been measured using both weighted averaging of emission lines and cross-correlation techniques against high-quality templates.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A111
- Title:
- Confirmed PN in M87 outer regions
- Short Name:
- J/A+A/620/A111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a kinematic study of a sample of 298 planetary nebulas (PNs) in the outer halo of the central Virgo galaxy M87 (NGC 4486). The line-of-sight velocities of these PNs are used to identify sub-components, to measure the angular momentum content of the main M87 halo, and to constrain the orbital distribution of the stars at these large radii. We use Gaussian mixture modelling to statistically separate distinct velocity components and identify the M87 smooth halo component, its unrelaxed substructures, and the intra-cluster (IC) PNs. We compute probability weighted velocity and velocity dispersion maps for the smooth halo, and its specific angular momentum profile ({lambda}_R_) and velocity dispersion profile. The classification of the PNs into smooth halo and ICPNs is supported by their different PN luminosity functions. Based on a K-S test, we conclude that the ICPN line-of-sight velocity distribution (LOSVD) is consistent with the LOSVD of the galaxies in Virgo subcluster A. The surface density profile of the ICPNS at 100kpc radii has a shallow logarithmic slope, -{alpha}_ICL_~=-0.8, dominating the light at the largest radii. Previous B-V colour and resolved star metallicity data indicate masses for the ICPN progenitor galaxies of a few x10^8^M_{sun}_. The angular momentum-related {lambda}_R_ profile for the smooth halo remains below 0.1, in the slow rotator regime, out to 135kpc average ellipse radius (170kpc major axis distance). Combining the PN velocity dispersion measurements for the M87 halo with literature data in the central 15kpc, we obtain a complete velocity dispersion profile out to R_avg_=135kpc. The {sigma}_halo_ profile decreases from the central 400km/s to about 270km/s at 2-10kpc, then rises again to ~=300+/-50km/s at 50-70kpc to finally decrease sharply to {sigma}_halo_~100km/s at R_avg_=135kpc. The steeply decreasing outer {sigma}_halo_ profile and the surface density profile of the smooth halo can be reconciled with the circular velocity curve inferred from assuming hydrostatic equilibrium for the hot X-ray gas. Because this rises to v_c,X_~700km/s at 200kpc, the orbit distribution of the smooth M87 halo is required to change strongly from approximately isotropic within R_avg_~60kpc to very radially anisotropic at the largest distances probed. The extended LOSVD of the PNs in the M87 halo allows the identification of several subcomponents: the ICPNs, the "crown" accretion event, and the smooth M87 halo. In galaxies likeM87, the presence of these sub-components needs to be taken into account to avoid systematic biases in estimating the total enclosed mass. The dynamical structure inferred from the velocity dispersion profile indicates that the smooth halo of M87 steepens beyond Ravg=60kpc and becomes strongly radially anisotropic, and that the velocity dispersion profile is consistent with the X-ray circular velocity curve at these radii without non-thermal pressure effects.
- ID:
- ivo://CDS.VizieR/J/A+A/557/A104
- Title:
- CO observations of post-AGB stars
- Short Name:
- J/A+A/557/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There is a group of binary post-AGB stars that show conspicuous near infrared (NIR) excess, which is usually assumed to arise from hot dust in very compact possibly rotating disks. These stars are surrounded by significantly fainter nebulae than the standard, well studied protoplanetary and planetary nebulae (PPNe, PNe). We aim to identify and study extended rotating disks around these stars and shed light on the role of disks in the formation and shaping of planetary nebulae. We present high-sensitivity mm-wave observations of CO lines in 24 objects of this type. The resulting CO lines are compared with profiles expected to arise from rotating disks, from both theoretical and observational grounds. We derive simple formulae that allow us to determine the mass of the CO-emitting gas and estimate its extent. The reliability and uncertainty of the methods are also widely discussed. CO emission is detected in most observed sources, and the line profiles show that the emissions very probably come from disks in rotation. We derive typical values of the disk mass between 10^-3^ and 10^-2^M_{sun}_, about two orders of magnitude lower than the (total) masses of standard PPNe. The high-detection rate (upper limits being not very significant) clearly confirm that the NIR excess of these stars arises from compact disks in rotation, which are likely the inner parts of those found here. Low-velocity outflows are also found in about eight objects with moderate expansion velocities of ~10km/s, to be compared with the velocities of about 100km/s often found in standard PPNe. Except for two sources with complex profiles, the outflowing gas in our objects represents a minor nebular component. Our simple estimates of the typical disk sizes yields values ~0.5-1arcsec, which is between 5x10^15^ and 3x10^16^cm. Estimates of the linear momenta carried by the outflows, which can only be performed in a few well studied objects, also yield moderate values when compared to the linear momenta that can be released by the stellar radiation pressure (contrary, again, to the case of the very massive and fast bipolar outflows in $standard$ PPNe that are strongly overluminous). The mass and dynamics of nebulae around various classes of post-AGB stars differ very significantly, and we can expect the formation of PNe with very different properties.
- ID:
- ivo://CDS.VizieR/J/A+A/408/1029
- Title:
- Coordinates of Galactic planetary nebulae
- Short Name:
- J/A+A/408/1029
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The table is a compilation of the positions of 1312 Galactic Planetary Nebulae (PNe). We have used the 2nd generation of the Guide Star Catalogue (GSC-II, Cat. <I/271>) as a reference astrometric catalogue to compile the positions of 1086 Galactic Planetary Nebulae (PNe) listed in the Strasbourg ESO Catalogue (SEC, Cat. <V/84>), its supplement and the version 2000 of the Catalogue of Planetary Nebulae. This constitutes about 75% of all known PNe. For these PNe, the ones with a known central star (CS) or with a small diameter, we have derived coordinates with an absolute accuracy of ~0.35" in each coordinate, which is the intrinsic astrometric precision of the GSC-II. For another 226, mostly extended, objects without a GSC-II counterpart we give coordinates based on the second epoch Digital Sky Survey (DSS-II). While these coordinates may have systematic offsets relative to the GSC-II of up to 5 arcsecs, our new coordinates usually represent a significant improvement over the previous catalogue values for these large objects. This is the first truly homogeneous compilation of PNe positions over the whole sky and the most accurate one available so far.
- ID:
- ivo://CDS.VizieR/J/MNRAS/480/2423
- Title:
- CORNISH project IV. Radio-selected galactic PN
- Short Name:
- J/MNRAS/480/2423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new radio-selected sample of PNe from the CORNISH survey. We find 90 new PNe, of which 12 are newly discovered and 78 are newly classified as PN. A further 47 previously suspected PNe are confirmed as such from the analysis presented here and 24 known PNe are detected. Eight sources are classified as possible PNe or other source types.
- ID:
- ivo://CDS.VizieR/J/A+A/603/A67
- Title:
- CRL618, MWC922 and M2-9 RRL spectra
- Short Name:
- J/A+A/603/A67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results from a pilot search for radio recombination line (RRL) emission at millimeter wavelengths in a small sample of pre-planetary nebulae (pPNe) and young PNe (yPNe) with emerging central ionized regions. Observations of the H30{alpha}, H31{alpha}, H39{alpha}, H41{alpha}, H48{beta}, H49{beta}, H51{beta}, and H55{gamma} lines at ~1 and ~3mm have been performed with the IRAM 30m radio telescope. These lines are excellent probes of the dense inner (<~150 au) and heavily obscured regions of these objects, where the yet unknown agents for PN-shaping originate. We detected mm-RRLs in three objects: CRL 618, MWC922, and M2-9. For CRL 618, the only pPN with previous published detections of H41{alpha}, H35{alpha}, and H30{alpha} emission, we find significant changes in the line profiles indicating that current observations are probing regions of the ionized wind with larger expansion velocities and mass-loss rate than ~29 years ago. In the case of MWC922, we observe a drastic transition from single-peaked profiles at 3mm (H39{alpha} and H41{alpha}) to double-peaked profiles at 1mm (H31{alpha} and H30{alpha}), which is consistent with maser amplification of the highest frequency lines; the observed line profiles are compatible with rotation and expansion of the ionized gas, probably arranged in a disk+wind system around a ~5-10M_{sun}_ central mass. In M2-9, the mm-RRL emission appears to be tracing a recent mass outburst by one of the stars of the central binary system. We present the results from non-LTE line and continuum radiative transfer models, which enables us to constrain the structure, kinematics, and physical conditions (electron temperature and density) of the ionized cores of our sample. We find temperatures Te~6000-17000K, mean densities ne~10^5^-10^8^cm^-3^, radial density gradients ne{prop.to}r^-alpha_n_^ whit alpha_n_~2-3.5, and motions of velocities of ~10-30km/s in the ionized wind regions traced by these mm-wavelength observations. We deduce mass-loss rates of dM_pAGB_/dt~=10^-6^-10^-7^M_{sun}_/yr, which are significantly higher than the values adopted by stellar evolution models currently in use and would result in a transition from the asymptotic giant branch to the PN phase faster than hitherto assumed.
- ID:
- ivo://CDS.VizieR/J/A+A/382/184
- Title:
- Crystalline silicates around evolved stars
- Short Name:
- J/A+A/382/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first paper in a series of three where we present the first comprehensive inventory of solid state emission bands observed in a sample of 17 oxygen-rich circumstellar dust shells surrounding evolved stars. The data were taken with the Short and Long Wavelength Spectrographs on board of the Infrared Space Observatory (ISO) and cover the 2.4 to 195{mu}m wavelength range. The spectra show the presence of broad 10 and 18{mu}m bands that can be attributed to amorphous silicates. In addition, at least 49 narrow bands are found whose position and width indicate they can be attributed to crystalline silicates. Almost all of these bands were not known before ISO.
- ID:
- ivo://CDS.VizieR/J/ApJ/697/1138
- Title:
- Discovery of PNe in M82
- Short Name:
- J/ApJ/697/1138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using an [OIII]{lambda}5007 on-band/off-band filter technique, we identify 109 planetary nebulae (PNe) candidates in the edge-on spiral galaxy M 82, using the FOCAS instrument at the 8.2m Subaru Telescope. The use of ancillary high-resolution Hubble Space Telescope Advanced Camera for Surveys H{alpha} imaging aided in confirming these candidates, helping to discriminate PNe from contaminants such as supernova remnants and compact HII regions. Once identified, these PNe reveal a great deal about the host galaxy; our analysis covers kinematics, stellar distribution, and distance determination. Radial velocities were determined for 94 of these PNe using a method of slitless spectroscopy, from which we obtain a clear picture of the galaxy's rotation.
