- ID:
- ivo://CDS.VizieR/J/A+A/561/A119
- Title:
- Spectra of stars and planetary nebulae
- Short Name:
- J/A+A/561/A119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fundamental parameters characterizing the end-state of intermediate-mass stars may be constrained by discovering planetary nebulae (PNe) in open clusters (OCs). Cluster membership may be exploited to establish the distance, luminosity, age, and physical size for PNe, and the intrinsic luminosity and mass of its central star. Four potential PN-OC associations were investigated to assess the cluster membership for the PNe. Radial velocities were measured from intermediate-resolution optical spectra, complemented with previous estimates in the literature.When the radial velocity study supported the PN/OC association, we analyzed whether other parameters (e.g., age, distance, reddening, central star brightness) were consistent with this conclusion.
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- ID:
- ivo://CDS.VizieR/J/A+A/573/A65
- Title:
- Spectra of young planetary nebulae
- Short Name:
- J/A+A/573/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of central stars of planetary nebulae was so far documented in just a few cases. However, spectra collected a few decades ago may provide a good reference for studying the evolution of central stars using the emission line fluxes of their nebulae. We investigated evolutionary changes of the [OIII] 5007{AA} line flux in the spectra of planetary nebulae. We compared nebular fluxes collected during a decade or longer. We used literature data and newly obtained spectra. A grid of Cloudy models was computed using existing evolutionary models, and the models were compared with the observations. An increase of the [OIII] 5007{AA} line flux is frequently observed in young planetary nebulae hosting H-rich central stars. The increasing nebular excitation is the response to the increasing temperature and hardening radiation of the central stars. We did not observe any changes in the nebular fluxes in the planetary nebulae hosting late-type Wolf-Rayet (WR) central stars. This may indicate a slower temperature evolution (which may stem from a different evolutionary status) of late-[WR] stars. In young planetary nebulae with H-rich central stars, the evolution can be followed using optical spectra collected during a decade or longer. The observed evolution of H-rich central stars is consistent with the predictions of the evolutionary models provided in the literature. Late-[WR] stars possibly follow a different evolutionary path.
- ID:
- ivo://CDS.VizieR/J/A+A/307/215
- Title:
- Spectrophotomety of planetary nebulae
- Short Name:
- J/A+A/307/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectrohotometric observations at high signal-to-noise ratio for a sample of 62 planetary nebulae are presented, together with the plasma and abundance analyses. The objects were selected homogeneously from the `Strasbourg-ESO Catalogue of Galactic Planetary Nebulae' by their height above the disk (over 300pc) and their H{beta} surface brightness (between 10^-12^ and 10^-14^mW/m^2^/arcsec^2^). The abundances of O, S, Ar, and Cl are tighly correlated. The N/O ratio shows a wide range of values, independent of He or O abundance.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/10
- Title:
- Spectroscopy of M31 globular clusters
- Short Name:
- J/ApJ/769/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of an [OIII]{lambda}5007 spectroscopic survey for planetary nebulae (PNe) located within the star clusters of M31. By examining R~5000 spectra taken with the WIYN+Hydra spectrograph, we identify 3 PN candidates in a sample of 274 likely globular clusters, 2 candidates in objects which may be globular clusters, and 5 candidates in a set of 85 younger systems. The possible PNe are all faint, between ~2.5 and ~6.8mag down the PN luminosity function, and, partly as a consequence of our selection criteria, have high excitation, with [OIII]{lambda}5007 to H{beta} ratios ranging from 2 to >~12. We discuss the individual candidates, their likelihood of cluster membership, and the possibility that they were formed via binary interactions within the clusters. Our data are consistent with the suggestion that PN formation within globular clusters correlates with binary encounter frequency, though, due to the small numbers and large uncertainties in the candidate list, this study does not provide sufficient evidence to confirm the hypothesis.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A109
- Title:
- Spectroscopy of Planetary Nebulae in NGC 5128
- Short Name:
- J/A+A/574/A109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planetary nebulae (PNe) are excellent tracers of the common low mass stars through their strong and narrow emission lines. The velocities of large numbers of PNe are excellent tracers of galaxy kinematics. NGC 5128, the nearest large early-type galaxy offers the possibility to gather a large PN sample. Imaging and spectroscopic observations of PNe in NGC 5128 were obtained to find PNe and measure their velocities. Combined with literature data, a large sample of high quality kinematic probes is assembled for dynamical studies in NGC 5128. NTT Imaging was obtained in 15 fields in NGC 5128 over 1 degree with EMMI and [OIII] and off-band filters. Newly detected emission sources, combined with literature PN, were used as input for FLAMES multi-fibre spectroscopy in MEDUSA mode. Spectra of the 4600-5100{AA} region were analysed and velocities were measured based on [OIII]4959,5007{AA} and often H{beta}. The chief results are catalogues of 1118 PN candidates and 1267 spectroscopically confirmed PNe in NGC 5128. The catalogue of PN candidates contains 1060 potential PNe discovered with NTT EMMI imaging and 58 from literature surveys. The spectroscopically confirmed PN catalogue has FLAMES radial velocity and emission line measurements for 1135 PNe, of which 486 are newly confirmed here. An additional 132 PN radial velocities are available from the literature. For 629 PNe observed with FLAMES, H-beta was measured in addition to the [OIII] emission lines. Nine targets show double-lined or more complex profiles (19 components in total), and their possible origin is discussed. FLAMES spectra of 48 globular clusters were also targetted, and 11 had emission lines detected (two with multiple components), but only 3 are PNe likely to belong to the host globular. Conclusions. The total of 1267 confirmed PNe in NGC 5128 with radial velocity measurements, of which 1135 have small velocity errors, is the largest such collection of individual kinematic probes in an early-type galaxy. This PN dataset, as well as the catalogue of 1118 PN candidates, are valuable resources for detailed investigation of the kinematics and stellar population of NGC 5128.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A54
- Title:
- Spectroscopy of 12 [WC] planetary nebulae
- Short Name:
- J/A+A/538/A54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planetary nebulae (PNe) around Wolf-Rayet [WR] central stars ([WR]PNe) constitute a particular photoionized nebula class that represents about 10% of the PNe with classified central stars. We analyse deep high-resolution spectrophotometric data of 12 [WR] PNe. This sample of [WR]PNe represents the most extensive analysed so far, at such high spectral resolution. We aim to select the optimal physical conditions in the nebulae to be used in ionic abundance calculations that will be presented in a forthcoming paper.
- ID:
- ivo://CDS.VizieR/J/MNRAS/409/881
- Title:
- Spectrosocpy of NGC 7009
- Short Name:
- J/MNRAS/409/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 7009 is a fascinating example of a high-excitation, elliptical planetary nebula (PN) containing circumnebular rings, and FLIERs and jets along the major axis. We present visual spectroscopy along multiple position angles through the nucleus, taken with the Observatorio Astronomico Nacional (Mexico); mid-infrared (MIR) spectroscopy and imaging acquired using the Infrared Space Observatory (ISO) and Spitzer Space Telescope (SST), and narrow-band imaging obtained using the Hubble Space Telescope (HST).
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/817
- Title:
- Spectrum of the planetary nebula NGC 6210
- Short Name:
- J/MNRAS/447/817
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution spectroscopy of NGC 6210, show that recombination line abundances of O^+2^ and Ne^+2^ are two to three times larger than forbidden line abundances, T_e_(O^+2^) is smaller than T_e_(N^+^) and possibly T_e_(S^+^), the ionized mass is ~0.07 M_{sun}_ and the progenitor zero-age main-sequence mass is 1.2-2 M_{sun}_. If electrons are in equilibrium, recombination lines are likely produced in a cold low-density medium. A photoionization model (cloudy 13.03) with a positive density gradient and two exciting sources, reproduced most of the optical spectrum, the temperature distribution of the nebula, HeII 4686/HeI 5876, [OII]3726/[OIII]5007 and [OII]3726/3729, but not the other density sensitive line ratios. Including fluorescence and recombination, we found good agreement with observed CII and CIII line intensities, OII and OIII model intensities which are 2.6 and 7.8 times smaller than observed and large erratic differences with observations in CIII, NII and NIII lines. UV and IR data suggest that [OII] emission is from a region ~6 times less dense than assumed by the model and that IR lines are produced in a medium where the density is ~1000/cm^3^. There may be a lower density medium beyond a dense ring described by the photoionization model, as well as a cold low-density component. A multicomponent model is required to reproduce the entire spectrum of NGC 6210.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A92
- Title:
- Spitzer/IRS analysis of the 30-micron sources
- Short Name:
- J/A+A/626/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis and comparison of the 30{mu}m dust features seen in the Spitzer Space Telescope spectra of 207 carbon-rich asymptotic giant branch (AGB) stars, post-AGB objects, and planetary nebulae (PNe) located in the Milky Way, the Magellanic Clouds (MCs), or the Sagittarius dwarf spheroidal galaxy (Sgr dSph), which are characterised by different average metallicities. We investigated whether the formation of the 30{mu}m feature carrier may be a function of the metallicity. Through this study we expect to better understand the late stages of stellar evolution of carbon-rich stars in these galaxies. Our analysis uses the "Manchester method" as a basis for estimating the temperature of dust for the carbon-rich AGB stars and the PNe in our sample. For post-AGB objects we changed the wavelength ranges used for temperature estimation, because of the presence of the 21{mu}m feature on the short wavelength edge of the 30{mu}m feature. We used a black-body function with a single temperature deduced from the Manchester method or its modification to approximate the continuum under the 30{mu}m feature. We find that the strength of the 30{mu}m feature increases until dust temperature drops below 400K. Below this temperature, the large loss of mass and probably the self-absorption effect reduces the strength of the feature. During the post-AGB phase, when the intense mass-loss has terminated, the optical depth of the circumstellar envelope is smaller, and the 30{um}m feature becomes visible again, showing variety of values for post-AGB objects and PNe, and being comparable with the strengths of AGB stars. In addition, the AGB stars and post-AGB objects show similar values of central wavelengths - usually between 28.5 and 29.5{mu}m. However, in case of PNe the shift of the central wavelength towards longer wavelengths is visible. The normalised median profiles for AGB stars look uniformly for various ranges of dust temperature, and different galaxies. We analysed the profiles of post-AGB objects and PNe only within one dust temperature range (below 200K), and they were also similar in different galaxies. In the spectra of 17 PNe and five post-AGB objects we found the broad 16-24{mu}m feature. Two objects among the PNe group are the new detections: SMP LMC 51, and SMP LMC 79, whereas in the case of post-AGBs the new detections are: IRAS 05370-7019, IRAS 05537-7015, and IRAS 21546+4721. In addition, in the spectra of nine PNe we found the new detections of 16-18{mu}m feature. We also find that the Galactic post-AGB object IRAS 11339-6004 has a 21{mu}m emission. Finally, we have produced online catalogues of photometric data and Spitzer IRS spectra for all objects that show the 30{mu}m feature. These resources are available online for use by the community. The most important conclusion of our work is the fact that the formation of the 30{mu}m feature is affected by metallicity. Specifically that, as opposed to more metal-poor samples of AGB stars in the MCs, the feature is seen at lower mass-loss rates, higher temperatures, and has seen to be more prominent in Galactic carbon stars. The averaged feature (profile) in the AGB, post-AGB objects, and PNe seems unaffected by metallicity at least between a fifth and solar metallicity, but in the case of PNe it is shifted to significantly longer wavelengths.
- ID:
- ivo://CDS.VizieR/J/AJ/135/726
- Title:
- Spitzer SAGE observations of LMC PNe
- Short Name:
- J/AJ/135/726
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present IRAC and MIPS images and photometry of a sample of previously known planetary nebulae (PNe) from the Surveying the Agents of a Galaxy's Evolution (SAGE) survey of the Large Magellanic Cloud (LMC) performed with the Spitzer Space Telescope. Of the 233 known PNe in the survey field, 185 objects were detected in at least two of the IRAC bands, and 161 detected in the MIPS 24um images. Color-color and color-magnitude diagrams are presented using several combinations of IRAC, MIPS, and Two Micron All Sky Survey magnitudes. The location of an individual PN in the color-color diagrams is seen to depend on the relative contributions of the spectral components which include molecular hydrogen, polycyclic aromatic hydrocarbons (PAHs), infrared forbidden line emission from the ionized gas, warm dust continuum, and emission directly from the central star. The sample of LMC PNe is compared to a number of Galactic PNe and found not to significantly differ in their position in color-color space. We also explore the potential value of IR PNe luminosity functions (LFs) in the LMC. IRAC LFs appear to follow the same functional form as the well-established [OIII] LFs although there are several PNe with observed IR magnitudes brighter than the cut-offs in these LFs.
