scholarly journals The Σ − D relation for planetary nebulae: Preliminary analysis

2007 ◽  
pp. 73-77 ◽  
Author(s):  
D. Urosevic ◽  
B. Vukotic ◽  
B. Arbutina ◽  
D. Ilic
Keyword(s):  
Preliminary Analysis ◽  
Surface Brightness ◽  
Supernova Remnant ◽  
Selection Effect ◽  
Planetary Nebulae

An analysis of the relation between radio surface brightness and diameter, so-called ? ? D relation, for planetary nebulae (PNe) is presented: i) the theoretical ? ? D relation for the evolution of bremsstrahlung surface brightness is derived; ii) contrary to the results obtained earlier for the Galactic supernova remnant (SNR) samples, our results show that the updated sample of Galactic PNe does not severely suffer from volume selection effect - Malmquist bias (same as for the extragalactic SNR samples) and; iii) we conclude that the empirical S ? D relation for PNe derived in this paper is not useful for valid determination of distances for all observed PNe with unknown distances. .

scholarly journals Planetary nebulae in the central region of the Galaxy

1964 ◽  
Vol 20 ◽  
pp. 41-45 ◽  
Author(s):  
L. Perek
Keyword(s):  
Central Region ◽  
Surface Brightness ◽  
Large Scale ◽  
Direct Determination ◽  
Planetary Nebulae ◽  
Galactic Centre ◽  
Large Numbers ◽  
The Galaxy ◽  
Objective Prism

Planetary nebulae are convenient objects for studying the large-scale structure of the Galaxy. Firstly, they are easily recognized up to considerable distances on plates taken through an objective prism, and secondly, methods have been devised by various authors to determine their distances from two observable quantities: angular diameter and surface brightness. The importance of the subsystem of planetary nebulae has been accentuated especially by the discoveries by Minkowski and Haro of large numbers of planetaries in the direction of the galactic centre. The distribution of planetaries on the sphere suggests that they are connected with the galactic nucleus, but no direct determination of their distances, which would either confirm or contradict this statement, is available. The most serious obstacle in studying the subsystem of planetaries is the lack of observing data. The aim of the reported paper (Perek 1963) is to give a tentative outline of the distribution of planetaries in space based on extensive new observing material.

scholarly journals Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors

2016 ◽  
Vol 12 (S323) ◽  
pp. 65-69 ◽  
Author(s):  
Jorge García-Rojas ◽  
Romano L. M. Corradi ◽  
Henri M. J. Boffin ◽  
Hektor Monteiro ◽  
David Jones ◽  
...  
Keyword(s):  
Planetary Nebulae ◽  
Tunable Filter ◽  
Close Binary ◽  
Chemical Abundances ◽  
Dual Nature ◽  
Gas Phases ◽  
Binary Evolution ◽  
The Universe ◽  
Central Stars

AbstractThe discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O ii ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O ii ORL emission is more centrally concentrated than that of [Oiii] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.

scholarly journals Kinematics of Planetary Nebulae in M51's Tidal Tail

2003 ◽  
Vol 209 ◽  
pp. 633-634
Author(s):  
John J. Feldmeier ◽  
J. Christopher Mihos ◽  
Patrick R. Durrell ◽  
Robin Ciardullo ◽  
George H. Jacoby
Keyword(s):  
Surface Brightness ◽  
Numerical Models ◽  
Planetary Nebulae ◽  
Tidal Tail ◽  
Low Surface Brightness ◽  
Galaxy Interaction ◽  
Self Consistent ◽  
The Galaxy ◽  
Interacting Systems ◽  
Kinematic Properties

The galaxy pair NGC 5194/95 (M51) is one of the closest and best known interacting systems. Despite its notoriety, however, many of its features are not well studied. Extending westward from NGC 5195 is a low surface brightness tidal tail, which can only be seen in deep broadband exposures. Our previous [O III] λ5007 planetary nebulae (PN) survey of M51 recovered this tidal tail, and presented us with a opportunity to study the kinematics of a galaxy interaction in progress. We report the results of a spectroscopy survey of the PN, aimed at determining their kinematic properties. We then use these data to constrain new self-consistent numerical models of the system.

scholarly journals Planetary Nebulae and the Pregalactic Helium Abundance

1989 ◽  
Vol 131 ◽  
pp. 213-213 ◽  
Author(s):  
Walter J. Maciel
Keyword(s):  
Chemical Composition ◽  
Recent Work ◽  
Planetary Nebulae ◽  
H Ii Regions ◽  
Helium Abundance

Recent work has emphasized the determination of the pregalactic helium abundance by mass Yp and the slope ΔY/ΔZ based on the chemical composition of both galactic and extragalactic H II regions (Pagel, 1987; Pagel et al., 1986).

scholarly journals Observations of Planetary Nebulae Haloes

2003 ◽  
Vol 209 ◽  
pp. 447-450
Author(s):  
Romano L.M. Corradi
Keyword(s):  
Mass Loss ◽  
Surface Brightness ◽  
Planetary Nebulae ◽  
Statistical Properties ◽  
Hydrogen Burning ◽  
Morphological Component ◽  
Loss Event ◽  
Central Stars

An improved database of ionized haloes around PNe has been built by adding the results of an extensive observational campaign to the data available in the literature. The new observations allowed us to discovered new haloes around CN 1-5, IC 2165, IC 2553, NGC 2792, NGC 2867, NGC 3918, NGC 5979, NGC 6578, PB 4, and possibly IC 1747.The global sample consists of 29 AGB haloes, that are believed to still contain information about the mass loss from the AGB progenitor star. Six of these haloes show a highly asymmetrical geometry that is tentatively ascribed to the interaction of the stellar outflow with the ISM.Another 5 PNe show candidate recombination haloes. These are produced by the recombination front that sets up when the stellar luminosity drops in its post-AGB evolution. The resulting, limb-brightened shell resembles a real AGB halo, but is not related to AGB any mass loss event.Double AGB haloes are found in at least 4 PNe.For 11 PNe, deep images are available, but no halo is found to a level of ≲ 10-3 the peak surface brightness of the inner nebula.These observations show us that ionized haloes are a common morphological component of PNe, being found in 70% of elliptical PNe for which adequately deep images exist. Statistical properties of the haloes are briefly discussed. Using the kinematical ages of the haloes and inner nebulae, we conclude that most of the PNe with detected haloes have hydrogen burning central stars.

scholarly journals The Σ – D relation for Galactic planetary nebulae: Application of orthogonal fitting procedure

2011 ◽  
Vol 7 (S283) ◽  
pp. 522-523
Author(s):  
Branislav Vukotić ◽  
Dejan Urošević
Keyword(s):  
Surface Brightness ◽  
Planetary Nebulae ◽  
Distance Determination ◽  
Fitting Procedure ◽  
Parameter Values

AbstractWe estimate the parameters of the radio surface brightness to diameter (Σ – D) relation for the sample of Galactic planetary nebulae (PNe). The bootstrap re-sampling and orthogonal offsets fitting procedure are applied. The orthogonal fitting procedure provides that the parameter values of D – Σ and Σ – D fits are invariant within the estimated uncertainties. We discuss the probability statistics of the fitted (log Σ = log A - β log D) relation and the resulting fit parameters which is indicative for PN distance determination.

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