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Start Over Subject planetary nebulae Validation Level 2
21. Angular dimensions of 312 planetary nebulae
ID:
ivo://CDS.VizieR/J/A+A/405/627
Title:
Angular dimensions of 312 planetary nebulae
Short Name:
J/A+A/405/627
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of direct measurements done on H{alpha} (or H{alpha}+[NII]) images of 312 planetary nebulae. For each planetary nebulae deconvolved FWHM and resolution size from Gaussian fit and from second-moment method and direct measurement at 10% level are presented.
22. ASKAP-EMU ESP LMC Radio Continuum Survey
ID:
ivo://CDS.VizieR/J/MNRAS/506/3540
Title:
ASKAP-EMU ESP LMC Radio Continuum Survey
Short Name:
J/MNRAS/506/3540
Date:
17 Jan 2022 11:54:41
Publisher:
CDS
Description:
We present an analysis of a new 120 deg^2^ radio continuum image of the Large Magellanic Cloud (LMC) at 888MHz with a bandwidth of 288MHz and beam size of 13.9"x12.1", from the Australian Square Kilometre Array Pathfinder (ASKAP) processed as part of the Evolutionary Map of the Universe (EMU) survey. The median Root Mean Squared noise is 58uJy/beam. We present a catalogue of 54612 sources, divided over a Gold list (30866 sources) complete down to 0.5mJy uniformly across the field, a Silver list (22080 sources) reaching down to <0.2mJy and a Bronze list (1666 sources) of visually inspected sources in areas of high noise and/or near bright complex emission. We discuss detections of planetary nebulae and their radio luminosity function, young stellar objects showing a correlation between radio luminosity and gas temperature, novae and X-ray binaries in the LMC, and active stars in the Galactic foreground that may become a significant population below this flux level. We present examples of diffuse emission in the LMC (HII regions, supernova remnants, bubbles) and distant galaxies showcasing spectacular interaction between jets and intracluster medium. Among 14333 infrared counterparts of the predominantly background radio source population we find that star-forming galaxies become more prominent below 3mJy compared to active galactic nuclei.We combine the new 888MHz data with archival Australia Telescope Compact Array data at 1.4GHz to determine spectral indices; the vast majority display synchrotron emission but flatter spectra occur too. We argue that the most extreme spectral index values are due to variability.
23. Astrometric data for 211 GAPN sample
ID:
ivo://CDS.VizieR/J/A+A/630/A150
Title:
Astrometric data for 211 GAPN sample
Short Name:
J/A+A/630/A150
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have compiled a catalogue of central stars of planetary nebulae (CSPN) with reliable distances and positions obtained from Gaia Data Release 2 (DR2) astrometry. Distances derived from parallaxes allow us to analyse the galactic distribution and estimate other parameters such as sizes, kinematical ages, bolometric magnitudes, and luminosities. Our objective is to analyse the information regarding distances together with other available literature data about photometric properties, nebular kinematics, and stellar effective temperatures to throw new light on this rapid and rather unknown evolutionary phase. We seek to understand how Gaia distances compare with other indirect methods commonly used and, in particular, with those derived from non-local thermodynamic equilibrium (non-LTE) models; how many planetary nebulae (PNe) populate the Galaxy; and how are they spatially distributed. We also aim to comprehend their intrinsic luminosities, range of physical sizes of the nebulae; how to derive the values for their kinematical ages; and whether those ages are compatible with those derived from evolutionary models. We considered all PNe listed in catalogues from different authors and in Hong Kong/AAO/Strasbourg/H{alpha} (HASH) database. By X-matching their positions with Gaia DR2 astrometry we were able to identify 1571 objects in Gaia second archive, for which we assumed distances calculated upon a Bayesian statistical approach. From those objects, we selected a sample of PNe with good quality parallax measurements and distance derivations, we which refer to as our Golden Astrometry PNe sample (GAPN), and obtained literature values of their apparent sizes, radial and expansion velocities, visual magnitudes, interstellar reddening, and effective temperatures. We found that the distances derived from DR2 parallaxes compare well with previous astrometric derivations of the United States Naval Observatory and Hubble Space Telescope, but that distances inferred from non-LTE model fitting are overestimated and need to be carefully reviewed. From literature apparent sizes, we calculated the physical radii for a subsample of nebulae that we used to derive the so-called kinematical ages, taking into account literature expansion velocities. Luminosities calculated with DR2 distances were combined with literature central stars Teff values in a Hertzsprung-Russell (HR) diagram to infer information on the evolutionary status of the nebulae. We compared their positions with updated evolutionary tracks finding a rather consistent picture. Stars with the smallest associated nebular radii are located in the flat luminosity region of the HR diagram, while those with the largest radii correspond to objects in a later stage, getting dimmer on their way to become a white dwarf. Finally, we commented on the completeness of our catalogue and calculated an approximate value for the total number of PNe in the Galaxy.
24. Automatic stellar spectral classification
ID:
ivo://CDS.VizieR/J/A+A/538/A76
Title:
Automatic stellar spectral classification
Short Name:
J/A+A/538/A76
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of a project aimed at deriving extinction-distances for thirty-five planetary nebulae, spectra of a few thousand stars were analyzed to determine their spectral type and luminosity class. We present here the automatic spectral classification process used to classify stellar spectra. This system can be used to classify any other stellar spectra with similar or higher signal-to-noise ratios. Spectral classification was performed using a system of artificial neural networks that were trained with a set of line-strength indices selected among the spectral lines most sensitive to temperature and the best luminosity tracers. The training and validation processes of the neural networks are discussed and the results of additional validation probes, designed to ensure the accuracy of the spectral classification, are presented.
25. BD+33 2642 and HD 112313 radial velocities
ID:
ivo://CDS.VizieR/J/A+A/563/L10
Title:
BD+33 2642 and HD 112313 radial velocities
Short Name:
J/A+A/563/L10
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the impact of binary interaction processes on the evolution of low- and intermediate-mass stars using long-term monitoring of their radial velocity. Here we report on our results on the central stars of two planetary nebulae (PNe): the well-studied spectrophotometric standard BD+33 2642 (central star of PNG 052.7+50.7) and HD 112313 (central star of PN LoTr5), the optical light of which is dominated by a rapidly rotating G star.
26. Binarity in planetary nebula central stars
ID:
ivo://CDS.VizieR/J/MNRAS/428/2118
Title:
Binarity in planetary nebula central stars
Short Name:
J/MNRAS/428/2118
Date:
21 Oct 2021
Publisher:
CDS
Description:
We still do not know what causes aspherical planetary nebula (PN) morphologies. A plausible hypothesis is that they are due to the presence of a close stellar or substellar companion. So far, only ~40 binary central stars of PN have been detected, almost all of them with such short periods that their binarity is revealed by photometric variability. Here we have endeavoured to discover binary central stars at any separation, thus determining the unbiased binary fraction of central stars of PN. This number, when compared to the binary fraction of the presumed parent population, can give a first handle on the origin of PN. By detecting the central stars in the I band we have searched for cool companions.
27. Binary central stars of SMC PNe
ID:
ivo://CDS.VizieR/J/A+A/561/A8
Title:
Binary central stars of SMC PNe
Short Name:
J/A+A/561/A8
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Optical Gravitational Lensing Experiment (OGLE), originally designed to search for microlensing events, provides a rich and uniform data set suitable for studying the variability of certain types of objects. We used the OGLE data to study the photometry of central stars of planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). In particular, we searched for close binary central stars with the aim to constrain the binary fraction and period distribution in the SMC. We also searched for PNe mimics and removed them from the PNe sample. We identified 52 counterparts of PNe in the SMC in the I-band images from the OGLE-II and OGLE-III surveys. We analysed the time-series photometry of the PNe. Spectra of the photometric variables were obtained to constrain the nature of the objects or search for additional evidence for binarity. Eight variables were found. Of these, seven objects are PNe mimics, including one symbiotic star candidate. One close binary central star of PN with a period of 1.15 or 2.31 day was discovered. The obtained binary fraction for the SMC PNe and the observational biases are discussed in terms of the OGLE observations.
28. Binary PNe towards the Galactic bulge
ID:
ivo://CDS.VizieR/J/A+A/496/813
Title:
Binary PNe towards the Galactic bulge
Short Name:
J/A+A/496/813
Date:
21 Oct 2021
Publisher:
CDS
Description:
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. An estimated close binary fraction of 12-21% is derived and is the first robust and independent validation of the prevailing 10-15% fraction estimated by Bond (2000, in Asymmetrical Planetary Nebulae II: From Origins to Microstructures, 199, 115). 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.
29. BVJH photometry of Andrews-Lindsay 1 field
ID:
ivo://CDS.VizieR/J/A+A/567/A1
Title:
BVJH photometry of Andrews-Lindsay 1 field
Short Name:
J/A+A/567/A1
Date:
21 Oct 2021
Publisher:
CDS
Description:
Andrews-Lindsay 1 is a pertinent open cluster because it may host the planetary nebula (PN) PHR 1315-6555, yet ambiguities linger concerning its fundamental parameters (>50% scatter). New multiband BVJHW_1-4_ photometry for cluster and field stars, in concert with observations of recently discovered classical Cepheids, were used to constrain the reddening and velocity-distance profiles along the sightline. That analysis yielded the following parameters for the cluster: E(J-H)=0.24+/-0.03, d=10.0+/-0.4kpc (d_JH_=9.9+/-0.6kpc, d_BV_=10.1+/-0.5kpc), and log{tau}=8.90+/-0.15. The steep velocity-distance gradient along l~305{deg} indicates that two remote objects sharing spatial and kinematic parameters (i.e., PHR 1315-6555 and Andrews-Lindsay 1) are associated, thus confirming claims that the PN is a cluster member. The new distance for PHR 1315-6555 is among the most precise established yet for a Galactic PN ({sigma}/d=4%).
30. BVRI photometric obs. of the PNe NGC 6337 & Sp 1
ID:
ivo://CDS.VizieR/J/ApJ/832/125
Title:
BVRI photometric obs. of the PNe NGC 6337 & Sp 1
Short Name:
J/ApJ/832/125
Date:
21 Oct 2021
Publisher:
CDS
Description:
A current issue in the study of planetary nebulae with close binary central stars (CSs) is the extent to which the binaries affect the shaping of the nebulae. Recent studies have begun to show a high coincidence rate between nebulae with large-scale axial or point symmetries and close binary stars. In addition, combined binary-star and spatiokinematic modeling of the nebulae have demonstrated that all of the systems studied to date appear to have their central binary axis aligned with the primary axis of the nebula. Here we add two more systems to the list, the CSs and nebulae of NGC 6337 and Sp 1. We show both systems to be low inclination, with their binary axis nearly aligned with our line of sight. Their inclinations match published values for the inclinations of their surrounding nebulae. Including these two systems with the existing sample statistically demonstrates a direct link between the central binary and the nebular morphology. In addition to the systems' inclinations we give ranges for other orbital parameters from binary modeling, including updated orbital periods for the binary CSs of NGC 6337 and Sp 1.