scholarly journals The Masses and Galactic Distribution of Southern Planetary Nebulae

1969 ◽  
Vol 143 (1) ◽  
pp. 79-95 ◽  
Author(s):  
B. L. Webster
Keyword(s):  
Planetary Nebulae ◽  
The Masses ◽  
Galactic Distribution

scholarly journals The Chemical Features of Galactic Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 575-575
Author(s):  
P. R. Amnuel
Keyword(s):  
Chemical Composition ◽  
Electron Temperature ◽  
Planetary Nebulae ◽  
Temperature Gradients ◽  
Element Abundances ◽  
Electron Temperature Gradients ◽  
The Masses ◽  
Progenitor Stars

The chemical composition of 218 galactic planatary nebulae is investigated, all the nebulae are divided into four classes according to the masses of the nebulae and progenitor stars. The values of local abundances, galactic abundances and electron temperature gradients are found for each class of nebulae. The correlations between element abundances are also investigated. The results are compared with theorical predictions.

scholarly journals The origin of the most luminous Planetary Nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 386-387
Author(s):  
Rebeca Galera-Rosillo ◽  
Romano L. M. Corradi ◽  
Bruce Balick ◽  
Karen Kwitter ◽  
Antonio Mampaso ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Planetary Nebulae ◽  
Stellar Systems ◽  
Systematic Effort ◽  
The Masses

AbstractAs part of a systematic effort to characterize the properties and progenitors of the most luminous planetary nebulae (PNe), we obtained a sample among the brightest PNe in two stellar systems of different metallicities: LMC (Z/Z⊙~0.5) and M31 (Z/Z⊙~1) by means of a combined effort with the VLT and the 10mGTC. Modelling of these data will allow us to infer the masses of the stellar progenitors, gaining insights into the controversial origin of the universal cutoff of the Planetary Nebulae Luminosity Function (PNLF).

The Correlation of PN Morphology and Parameters

2003 ◽  
Vol 209 ◽  
pp. 431-438
Author(s):  
Arturo Manchado
Keyword(s):  
Stellar Population ◽  
Planetary Nebulae ◽  
Stellar Mass ◽  
Galactic Latitude ◽  
Complete Sample ◽  
Chemical Abundances ◽  
Galactic Distribution ◽  
Pn Morphology

The morphology of a complete sample of 255 northern planetary nebulae (PNe) was studied and correlated with the nebular parameters. PNe were classified according to the following scheme: round (R, 25%), elliptical (E, 58% of the sample), and bipolar (B, 17%). Bipolars include the quadrupolar subsample. A subclass of pointsymmetric and multiple shell PNe was also found. Nine per cent of ellipticals and 46% of bipolars were found to be pointsymmetric. Thirty-five per cent of the round and 22% of the elliptical PNe were found to be multiple shell PNe (MSPNe). Galactic latitude was found to be different for each morphological class (|b| = 8°, 5° and 2° for types R, E, and B, respectively). Galactic height was also found to vary: 〈z〉 = 647, 276, and 100 pc for categories R, E, and B, respectively. Segregation according to the chemical abundances was also found, with helium abundances of 0.10, 0.12, and 0.14 and N/O of 0.21, 0.31, and 1.33 for types R, E, and B, respectively. Both galactic distribution and chemical abundances point to a different stellar population for each morphological class, the round and bipolar types being the result of low and high stellar mass progenitor evolution, respectively.

scholarly journals A Speculation into the Origin of Neutral Globules in Planetary Nebulae: Could the Helix’s Comets Really be Comets?

1995 ◽  
Vol 12 (2) ◽  
pp. 170-173
Author(s):  
Grant Gussie
Keyword(s):  
Solar System ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Central Star ◽  
Oort Cloud ◽  
Asymptotic Giant Branch ◽  
Neutral Gas ◽  
Red Giant ◽  
The Masses

AbstractA novel explanation for the origin of the cometary globules within NGC 7293 (the ‘Helix’ planetary nebula) is examined, namely that these globules originate as massive cometary bodies at large astrocentric radii. The masses of such hypothetical cometary bodies would have to be several orders of magnitude larger than those of any such bodies observed in our solar system in order to supply the observed mass of neutral gas. It is, however, shown that comets at ‘outer Oort cloud’ distances are likely to survive past the red giant and asymptotic giant branch evolutionary phases of the central star, allowing them to survive until the formation of the planetary nebula. Some observational tests of this hypothesis are proposed.

Angular Diameters of Magellanic Cloud Planetary Nebulae Obtained using Speckle Interferometry

1985 ◽  
Vol 6 (1) ◽  
pp. 54-55
Author(s):  
P. R. Wood ◽  
M. S. Bessell ◽  
M. A. Dopita
Keyword(s):  
Small Diameter ◽  
Planetary Nebulae ◽  
Speckle Interferometry ◽  
Mean Value ◽  
Magellanic Cloud ◽  
Angular Diameter ◽  
Ionized Gas ◽  
The Masses ◽  
Lower Limits ◽  
Angular Diameters

AbstractAngular diameters of Magellanic Cloud planetary nebulae obtained using speckle interferometry on the AAT are presented. The mass of ionized gas in each nebula is derived from the angular diameter and published Hβ line fluxes; the derived masses range from 0.005M⊙ to 0.19M⊙, with a mean value of 0.08M⊙. All the planetary nebulae observed are relatively small (diameter ≲0.13pc), young (age ≲ 2500 years), bright and dense. They are therefore almost certainly only partially ionized, so that the masses derived for the ionized parts of the nebula are lower limits to the total nebula mass.

The Possible Progenitors of Planetary Nebulae among OH/IR Stars

1991 ◽  
Vol 9 (2) ◽  
pp. 298-299
Author(s):  
P. te Lintel Hekkert ◽  
A. A. Zijlstra
Keyword(s):  
Planetary Nebulae ◽  
Close Correlation ◽  
Outflow Velocity ◽  
Ir Stars ◽  
Galactic Distribution

AbstractBased on a new sample of (IRAS based) OH/IR stars, and a catalogue of planetary nebulae compiled by Acker (1983), we study the relation between these two groups of objects, in terms of the kinematics and the Galactic distribution. In contrast with earlier analyses of samples of OH/IR stars, we find a close correlation between the kinematics of the planetary nebulae and the IRAS based sample of OH/IR stars. In particular, we find that the distribution of the planetary nebulae (PN) shows a good correlation with the OH/IR stars which have a low outflow velocity (Vexp < 12.5 km s−1). Whether the high outflow velocity OH/IR stars also have a counterpart among PN is not clear.

scholarly journals Masses of the central stars of Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 107-107 ◽  
Author(s):  
S.K. Górny ◽  
G. Stasińska ◽  
R. Tylenda
Keyword(s):  
Surface Brightness ◽  
Planetary Nebulae ◽  
Large Sample ◽  
The Third ◽  
V Band ◽  
The Masses ◽  
Central Stars ◽  
Angular Radius

The aim of this study is to derive the masses of the central stars (CSPN) for a large sample of the planetary nebulae (PN). These masses, M∗, are derived from the observed PN positions in three diagnostic diagrams and their comparison with evolutionary tracks of model PN. Two of the diagrams, namely LZan(H) versus TZan(H) and Mv versus Rneb, have already been used in numerous studies. The third one, SHβ versus SV, has recently been introduced by Górny, Stasińska & Tylenda (1996, hereinafter GST96). Here SHβ is the nebular surface brightness in Hβ and Sv is defined as Fv/(πθ2), where Fv is the stellar flux in the V band and θ is the observed nebular angular radius.

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