- ID:
- ivo://CDS.VizieR/J/ApJ/689/194
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/ApJ/689/194
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galactic planetary nebula (PN) distances are derived, except in a small number of cases, through the calibration of statistical properties of PNs. Such calibrations are limited by the accuracy of individual PN distances, which are obtained with several nonhomogeneous methods, each carrying its own set of liabilities. In this paper we use the physical properties of the PNs in the Magellanic Clouds and their accurately known distances to recalibrate the Shklovsky/Daub (1982ApJ...260..612D) distance technique. Our new calibration is very similar (within 1%) to the commonly used distance scale by Cahn et al. (1992, Cat. J/A+AS/94/399), although there are important differences. We present a catalog of Galactic PN distances using our recalibration, which can be used for future applications, and compare the best individual Galactic PN distances to our new and several other distance scales, both in the literature and newly recalibrated by us, finding that our scale is the most reliable to date.
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- ID:
- ivo://CDS.VizieR/J/AJ/115/1989
- Title:
- Distances of galactic planetary nebulae
- Short Name:
- J/AJ/115/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is well known that the IRAS colors of planetary nebulae (PNe) are very similar to blackbody colors. Taking account of this characteristic, we define a new method to obtain some information about the distance to PNe by blackbody fitting of IRAS four-band fluxes, assuming these fluxes are due to thermal emission from the nebular dust envelope. The fit should have two free parameters - the dust temperature TD and the distance-dependent "scaling factor" A - under the assumption of uniform dust mass. We find that the A-values have a good correlation with published distances. The scaling factor A could be a more effective distance scale than others, because many PNe have been detected as IRAS sources and the extinction of IRAS fluxes is not so severe, and is known. We also find that TD is concentrated between 100 and 200K, with a typical value of about 150K.
- ID:
- ivo://CDS.VizieR/J/MNRAS/353/589
- Title:
- Distances of planetary nebula
- Short Name:
- J/MNRAS/353/589
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distances of planetary nebulae (PNe) are still quite uncertain. Although observational estimates are available for a small proportion of PNe, based on statistical parallax and the like, such distances are very poorly determined for the majority of galactic PNe. In particular, estimates of so-called 'statistical' distance appear to differ by factors of ~2.7. We point out that there is a well-defined correlation between the 5-GHz luminosity of the sources, L_5_, and their brightness temperatures, T_B_.
- ID:
- ivo://CDS.VizieR/J/ApJ/753/172
- Title:
- Dust classification in Galactic PNe
- Short Name:
- J/ApJ/753/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Spitzer/Infrared Spectrograph (IRS) spectra of 157 compact Galactic planetary nebulae (PNe). These young PNe provide insight on the effects of dust in early post-asymptotic giant branch evolution, before much of the dust is altered or destroyed by the hardening stellar radiation field. Most of the selected targets have PN-type IRS spectra, while a few turned out to be misclassified stars. We inspected the group properties of the PN spectra and classified them based on the different dust classes (featureless or F, carbon-rich dust or CRD, oxygen-rich dust or ORD, mixed-chemistry dust or MCD) and subclasses (aromatic and aliphatic, and crystalline and amorphous). All PNe are characterized by dust continuum and more than 80% of the sample shows solid-state features above the continuum, in contrast with the Magellanic Cloud sample where only ~40% of the entire sample displays solid-state features; this is an indication of the strong link between dust properties and metallicity.
- ID:
- ivo://CDS.VizieR/J/A+AS/102/451
- Title:
- Emission-line stars and PNe in the SMC
- Short Name:
- J/A+AS/102/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An objective-prism survey of the Small Magellanic Cloud (SMC) has been performed through an H-{alpha} + [NII] interference filter, using the 90cm Curtis Schmidt telescope of Cerro Tololo. 1898 emission-line objects have been detected in the main body of this galaxy, almost quadrupling the number of those found in the same region by the previous objective-prism surveys. Among these objects are newly discovered planetary nebulae, compact HII regions and late-type stars. Continuum intensity, as well as the shape and relative strength of the H-{alpha} emission-line have been estimated; coordinates, cross-identifications for the listed objects are provided. The original paper contains in addition finding charts.
- ID:
- ivo://CDS.VizieR/J/A+A/431/565
- Title:
- Evolved stars in the MSX survey
- Short Name:
- J/A+A/431/565
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the evolution of oxygen- and carbon-rich AGB stars, post-AGB objects, and planetary nebulae using data collected mainly from the MSX catalogue. Magnitudes and colour indices are compared with those calculated from a grid of synthetic spectra that describe the post-AGB evolution beginning at the onset of the superwind.
- ID:
- ivo://CDS.VizieR/J/MNRAS/490/5063
- Title:
- Extended sources in SCORPIO at 2.1GHz
- Short Name:
- J/MNRAS/490/5063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of a large sample of extended radio sources in the Stellar Continuum Originating from Radio Physics In Ourgalaxy (SCORPIO) field, observed and resolved by the Australia Telescope Compact Array. SCORPIO, a pathfinder project for addressing the early operations of the Australia SKA Pathfinder, is a survey of ~5 square degrees between 1.4 and 3.1GHz, centred at l=343.5{deg}, b=0.75{deg}, and with an angular resolution of about 10 arcsec. It is aimed at understanding the scientific and technical challenges to be faced by future Galactic surveys. With a mean sensitivity around 100uJy/beam and the possibility to recover angular scales at least up to 4 arcmin, we extracted 99 extended sources, 35 of them detected for the first time. Among the 64 known sources 55 had at least a tentative classification in literature. Studying the radio morphology and comparing the radio emission with infrared we propose as candidates six new HII regions, two new planetary nebulae, two new luminous blue variable or Wolf-Rayet stars, and three new supernova remnants. This study provides an overview of the potentiality of future radio surveys in terms of Galactic source extraction and characterization and a discussion on the difficulty to reduce and analyse interferometric data on the Galactic plane.
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/718
- Title:
- Extremely faint planetary nebulae in SDSS
- Short Name:
- J/MNRAS/436/718
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using ~1700000 target- and sky-fibre spectra from the Sloan Digital Sky Survey (SDSS), we have carried out a systematic search for Galactic planetary nebulae (PNe) via detections of the [OIII] {lambda}{lambda}4959, 5007 lines. Thanks to the excellent sensitivity of the SDSS spectroscopic surveys, this is by far the deepest search for PNe ever taken, reaching a surface brightness of the [OIII] {lambda}5007 line down to about 29.0mag/arcsec^2^. The search leads to the recovery of 13 previously known PNe in the Northern and Southern Galactic Caps. In total, 44 new PN candidates are identified, including seven candidates of multiple detections and 37 candidates of single detection. The seven candidates of multiple detections are all extremely large (between 21 and 154arcmin) and faint, located mostly in the low Galactic latitude region and with a kinematics similar to disc stars. After checking their images in H{alpha} and other bands, three of them are probably HII regions, one is probably associated with a new supernova remnant, another one is possibly a true PN and the remaining two could be either PNe or supernova remnants. Based on sky positions and kinematics, seven candidates of single detection probably belong to the halo population. If confirmed, they will increase the number of known PNe in the Galactic halo significantly. All the newly identified PN candidates are very faint, with a surface brightness of the [OIII] {lambda}5007 line between 27.0-30.0mag/arcsec^2^, and very challenging to be discovered with previously employed techniques (e.g. slitless spectroscopy, narrow-band imaging), and thus may greatly increase the number of `missing' faint PNe. Our results demonstrate the power of large-scale fibre spectroscopy in hunting for ultrafaint PNe and other types of emission line nebulae. Combining the large spectral data bases provided by the SDSS and other on-going projects (e.g. the LAMOST Galactic surveys), it is possible to build a statistically meaningful sample of ultrafaint, large, evolved PNe, thus, improving the census of Galactic PNe.
- ID:
- ivo://CDS.VizieR/J/ApJ/417/209
- Title:
- Faint planetary nebulae in Magellanic Clouds
- Short Name:
- J/ApJ/417/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The accuracy of spectrophotometry for Magellanic Cloud planetary nebulae is limited by a number of physical effects and operational difficulties: atmospheric dispersion, wavelength-dependent seeing, pointing and guiding errors, and a background of numerous stars and diffuse emission. We describe procedures to minimize the impact of some of these. We then compare our results for both bright and faint objects with published values. There are a few exceptional cases (e.g., LMC 89), but generally we find that bright planetary nebulae in the Clouds have been observed with high accuracy. On the other hand, observations of the faint sample from Jacoby (1980ApJS...42....1J) suffer seriously from many of these effects. We also compare published {lambda}5007 photometry with new CCD photometry for nine faint planetary nebulae. We find the photographic photometry presented by Jacoby (1980ApJS...42....1J) to be accurate to 0.26mag. Fluxes for the fainter objects that are derived from spectrophotometry (Boroson & Liebert, 1989ApJ...339..844B) are found to be less reliable. In comparison, spectrophotometry using the observational techniques presented in this paper provides reliable absolute fluxes. With these improved observations, we review the correlations presented by Kaler & Jacoby (1990ApJ...362..491K, 1991ApJ...382..134K) between abundance ratios and central star mass. The new results fit our earlier correlation for N/O, strengthen that for He/H, and change little about those for C/O and O/H.
- ID:
- ivo://CDS.VizieR/J/A+A/553/A126
- Title:
- Far-UV spectra of PN central stars
- Short Name:
- J/A+A/553/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The occurrence of stellar wind in the central star of a planetary nebula (CSPN) can be revealed by the presence of P Cygni profiles of high-excitation lines overimposed on its stellar continuum. We have examined the entire Far-Ultraviolet Spectroscopic Explorer FUSE archive and merged all useful spectroscopic observations of CSPNe to produce the highest quality spectra that can be used to assess the occurrence of stellar winds. Furthermore, the individual spectra of each CSPN have been compared to search for variability in the P Cygni profile. P Cygni profiles of high-excitation lines have been found in 44 CSPNe, with a clear correlation between the ionization potential of the lines and the effective temperature of the star.
