scholarly journals Morphology and ionization characteristics of planetary nebulae PB 1 and PC 19

2020 ◽  
Vol 496 (1) ◽  
pp. 814-831
Author(s):  
Rahul Bandyopadhyay ◽  
Ramkrishna Das ◽  
Soumen Mondal ◽  
Samrat Ghosh
Keyword(s):  
Planetary Nebulae ◽  
Physical Parameters ◽  
Plasma Parameters ◽  
Density Profiles ◽  
Bipolar Structure ◽  
Elemental Abundances ◽  
Ionization Structure ◽  
Evolutionary Trajectories ◽  
C And N ◽  
Central Stars

ABSTRACT We present results of our study of two planetary nebulae (PNe), PB1 and PC 19. We use the optical spectra of these two PNe observed at 2 m Himalayan Chandra Telescope and also archival and literature data for the study. We use the morphokinematic code shape to construct 3D morphologies of the PNe and the photoionization code cloudy to model the observed spectra. The 3D model of PB 1 consists of an elongated shell surrounded by a bipolar halo and that of PC 19 consists of an open lobed bipolar structure and a spiral filamentary pair. We analyse the ionization structure of the PNe by deriving several plasma parameters and by photoionization modelling. We estimate the elemental abundances of the elements, He, C, N, O, Ne, S, Ar, and Cl, from our analysis. We find He, C, and N abundances to be significantly higher in case of PB 1. We estimate different physical parameters of the central stars, namely effective temperature, luminosity, and gravity, and of the nebula, namely hydrogen density profiles, radii, etc., from photoionization modelling. We estimate distances to the PNe as ∼4.3 kpc for PB 1 and as ∼5.6 kpc for PC 19 by fitting the photoionization models to absolute observed fluxes. Progenitor masses are estimated from theoretical evolutionary trajectories and are found to be ∼1.67 and ∼2.38 M⊙ for PB 1 and PC 19, respectively.

scholarly journals New advances in the field of planetary nebulae from ultraviolet observations

2011 ◽  
Vol 7 (S283) ◽  
pp. 45-52 ◽  
Author(s):  
Luciana Bianchi
Keyword(s):  
Planetary Nebulae ◽  
Ionic Species ◽  
Physical Parameters ◽  
Mass Relation ◽  
Chemical Enrichment ◽  
Intermediate Mass Stars ◽  
Ionization Structure ◽  
C And N ◽  
Ultraviolet Observations ◽  
Critical Constraints

AbstractThe ultraviolet (UV) domain, in particular shortwards of Lyα, provides unique information to unravel the physical parameters of Central Stars of Planetary Nebulae (CSPNe) and the paths for this elusive final stage of stellar evolution, thanks to a wealth of diagnostic transitions from ionic species not observable at other wavelengths. Intermediate mass stars are the major providers of important elements like C and N. Understanding how they shed most of their initial mass is critical for understanding the chemical enrichment of the ISM. Mass-loss diagnostic lines abound at UV wavelengths, and when the CSPN reaches the hottest Teff before turning on the WD-cooling sequence, and the wind fades, the last wind lines to disappear are found in the far-UV, as well as diagnostic lines for elements such as Ne. This domain also offers a host of H2 transitions, tracing the circum-stellar material expelled in previous phases. UV images and spectra of PNe add critical constraints to their ionization structure and to some abundances. Finally, the recent GALEX sky surveys in two UV bands afforded the first unbiased census of hot white dwarfs (WD) and post-AGB objects in the Milky Way, significantly expanding known catalogs and providing statistical constraints to the initial-final mass relation.

scholarly journals Catalogue of the central stars of planetary nebulae

2020 ◽  
Vol 640 ◽  
pp. A10
Author(s):  
W. A. Weidmann ◽  
M. B. Mari ◽  
E. O. Schmidt ◽  
G. Gaspar ◽  
M. M. Miller Bertolami ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Late Stage ◽  
Planetary Nebulae ◽  
Surface Gravity ◽  
Physical Parameters ◽  
Evolutionary Models ◽  
Pertinent Information ◽  
Central Stars ◽  
Statistical Improvement ◽  
Magnitude Estimates

Planetary nebulae represent a potential late stage of stellar evolution, however, their central stars (CSPNe) are relatively faint and, therefore, pertinent information is available for merely < 20% of the Galactic sample. Consequently, the literature was surveyed to construct a new catalogue of 620 CSPNe featuring important spectral classifications and information. The catalogue supersedes the existing iteration by 25% and includes physical parameters such as luminosity, surface gravity, temperature, magnitude estimates, and references for published spectra. The marked statistical improvement enabled the following pertinent conclusions to be determined: the H-rich/H-poor ratio is 2:1, there is a deficiency of CSPNe with types [WC 5-6], and nearly 80% of binary central stars belong to the H-rich group. The last finding suggests that evolutionary scenarios leading to the formation of binary central stars interfere with the conditions required for the formation of H-poor CSPN. Approximately 50% of the sample with derived values of log L⋆, log Teff, and log g, exhibit masses and ages consistent with single stellar evolutionary models. The implication is that single stars are indeed able to form planetary nebulae. Moreover, it is shown that H-poor CSPNe are formed by higher mass progenitors. The catalogue is available through the Vizier database.

scholarly journals The global properties of planetary nebulae in the Galactic Bulge

1993 ◽  
Vol 153 ◽  
pp. 117-132
Author(s):  
G. Stasińska
Keyword(s):  
Planetary Nebulae ◽  
Physical Parameters ◽  
Galactic Bulge ◽  
Global Properties ◽  
Central Stars

After a discussion of the methods used to derive the physical parameters of planetary nebulae and their central stars, the global properties of planetary nebulae in the Galactic bulge are reviewed, and compared to those of planetary nebulae in different contexts.

Physical parameters for 12 planetary nebulae and their central stars in the Magellanic Clouds

1987 ◽  
Vol 320 ◽  
pp. 159 ◽  
Author(s):  
Lawrence H. Aller ◽  
Charles D. Keyes ◽  
Stephen P. Maran ◽  
Theodore R. Gull ◽  
Andrew G. Michalitsianos ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Magellanic Clouds ◽  
Physical Parameters ◽  
Central Stars

Physical Parameters for 12 Planetary Nebulae and Their Central Stars in the Magellanic Clouds: Erratum

1988 ◽  
Vol 326 ◽  
pp. 1040
Author(s):  
Lawrence H. Aller ◽  
Charles D. Keyes ◽  
Stephen P. Maran ◽  
Theodore R. Gull ◽  
Andrew G. Michalitsianos ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Magellanic Clouds ◽  
Physical Parameters ◽  
Central Stars

scholarly journals Mass Loss from Central Stars of Planetary Nebulae

1983 ◽  
Vol 103 ◽  
pp. 323-335 ◽  
Author(s):  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Large Fraction ◽  
Planetary Nebulae ◽  
Stellar Winds ◽  
Large Interval ◽  
Ionization Structure ◽  
Central Stars

Stellar winds have been revealed in a large fraction of central stars of planetary nebulae from P Cygni profiles observed with the IUE satellite. The relevant lines are essentially the resonance lines NV λ 1240, Si IV λ 1397, CIV λ 1549 and the subordinate lines OIV∗ λ 1342, 0V∗ λ 1371, NIV∗ λ 1579. Edge velocities are of the order of 1000-3000 km s−1, similar to the case of population I O stars. Detailed determinations of the mass loss rate have been performed for NGC 6543, NGC 2371, IC 2149 and IC 3568 with values between 4.10−9 to 7. 10−7 Mo yr−1. The accuracy of these determinations is not well known. It is however clear from the variety of observed profiles in these and in several other objects that properties of the winds (ionization structure, etc.) varies considerably from object to object and that very likely the mass loss rate will span over a large interval. Some possible consequences of these winds are discussed.

scholarly journals Physical parameters and chemical abundances in bipolar PNe

2011 ◽  
Vol 7 (S283) ◽  
pp. 336-337
Author(s):  
Roberto D. D. Costa ◽  
Daniel M. Faes ◽  
Christophe Morisset
Keyword(s):  
Numerical Simulations ◽  
Planetary Nebulae ◽  
Central Star ◽  
Physical Parameters ◽  
Intrinsic Properties ◽  
Matter Distribution ◽  
Chemical Abundances ◽  
Bipolar Structure ◽  
Self Consistent ◽  
First Results

AbstractBipolar nebulae constitute a large subset of the planetary nebulae population. We present the first results of a project aimed to map physical parameters and chemical abundances across extended planetary nebulae with bipolar structure. These results can be used as input and constraints into numerical simulations in order to reproduce their properties in the visual band of the spectrum. This provides a way to examine the non-homogeneity present in this kind of object, as well as a tool to derive their intrinsic properties, like tridimensional geometry and matter distribution, central star properties, distance, and other properties in a self-consistent way. Here we show our results for two of these objects: IC 4406 and NGC 6572.

scholarly journals Time-Dependent Effects in Planetary Nebulae Caused by Thermal Pulses in Central Stars

1978 ◽  
Vol 76 ◽  
pp. 211-211
Author(s):  
R. Tylenda
Keyword(s):  
Time Scale ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Theoretical Models ◽  
Emission Lines ◽  
Time Dependent ◽  
Stationary Model ◽  
Ionization Structure ◽  
Thermal Pulses ◽  
Central Stars

Nuclei of planetary nebulae are suspected to go through thermal pulses. A time scale of such pulses is of the order of 10–103 years and so it is comparable with the time of recombination in a typical planetary nebula. Theoretical models have been constructed to study evolution of ionization structure of nebulae in which the spectrum of ionizing radiation varies with time. Resulting intensities of emission lines are compared with those produced by stationary model nebulae.

scholarly journals Atomic processes in planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 131-138
Author(s):  
Xiaowei Liu
Keyword(s):  
Cross Sections ◽  
Plasma Diagnostics ◽  
Heavy Element ◽  
Planetary Nebulae ◽  
Atomic Processes ◽  
Physical Conditions ◽  
Elemental Abundances ◽  
Ionization Structure ◽  
Cold Plasmas ◽  
The One

AbstractProgress in the study of the atomic processes in planetary nebulae (PNe) is reviewed, focusing on the literature published since the last IAU symposium on PNe five years ago. High quality photoionization cross sections and recombination coefficients are now available for the first six ions of the trans-iron elements selenium and krypton, enabling robust modeling of their ionization structure and consequently converting the measured ionic abundances to elemental abundances. Major progress has been achieved in utilizing the recombination spectra of helium and heavy element ions to probe the nebular physical conditions. New ab initio, density-dependent effective recombination coefficients have been calculated for the recombination spectra of O ii and N ii, down to very low temperatures (~ 100–300 K). Plasma diagnostics based entirely on those heavy element recombination lines are developed and applied to the observations. It is shown that these heavy element recombination lines originate predominately from cold plasmas of temperatures ~ 1,000 K, in agreement with the predictions of the bi-abundance model that has been proposed to explain the dichotomy of nebular plasma diagnostics and abundance determinations using collisional excited lines (CELs) on the one hand and optical recombination lines (ORLs) on the other.

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