scholarly journals De-Centered Central Stars of Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 541-542 ◽  
Author(s):  
Aubrie McLean ◽  
Martín A. Guerrero ◽  
Robert A. Gruendl ◽  
You-Hua Chu
Keyword(s):  
Binary System ◽  
Mass Loss ◽  
Planetary Nebulae ◽  
Central Star ◽  
Large Sample ◽  
Preliminary Results ◽  
Wide Range ◽  
Central Stars

The origin of the wide range of morphologies observed in planetary nebulae (PNe) is not well established. The influence of a binary companion of the central star can naturally explain this variety of morphologies, but very few PNe have known binary central stars. The evolution of the binary system with mass loss may result in the displacement of the central star from the nebular center. The large sample of PNe observed by HST is being used to search for de-centered central stars. Preliminary results indicate that the occurrence of de-centered central stars is widespread among all morphological types of PNe.

scholarly journals Mass loss from central stars of planetary nebulae

1981 ◽  
Vol 59 ◽  
pp. 45-50
Author(s):  
Mario Perinotto ◽  
Piero Benvenuti ◽  
Carla Cacciari
Keyword(s):  
Mass Loss ◽  
Planetary Nebula ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Planetary Nebulae ◽  
Central Star ◽  
High Resolution Spectrum ◽  
Preliminary Evaluation ◽  
Associated Mass ◽  
Central Stars

AbstractFrom a high resolution spectrum taken with IUE, the central star of the planetary nebula IC 2149 is found to exibit a wind with edge velocity of 1440 ± 100 km s-1. Our preliminary evaluation of the associated mass loss rate gives 10-8 M0 yr-1. Other planetary nebulae nuclei are studied with low resolution IUE spectra and indications are found of mass loss rates consistent with the above value.

scholarly journals Evolution of Planetary Nebulae: A comparison with Observed Central Stars

1989 ◽  
Vol 131 ◽  
pp. 543-544
Author(s):  
M. Schmidt-Voigt
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Planetary Nebulae ◽  
Central Star ◽  
Evolutionary Time ◽  
Line Model ◽  
Highly Nonlinear ◽  
Visual Magnitude ◽  
Central Stars

The relation between nebular excitation E(He II λ4686/Hβ-ratio) and absolute visual magnitude of the central star (CS) is compared with hydrodynamical models of planetary nebulae (PNe) from Schmidt-Voigt and Köppen (Astron. Astrophys., 174, 211 and 223) (see figure below, data from D. Schönberner, Astron. Astrophys., 169, 189). Models marked by drawn lines have a 0.644 M⊙ CS following a Schönberner track, an initially expelled PN of 0.1 M⊙, and different mass loss rates of the precursor star on the AGB, described by the Reimers parameter η;η = 1 corresponds to a mass loss rate of 1.55 × 10−6M⊙ α−1 the dashed line model has a higher initially expelled mass (0.3 M⊙), the dash-dotted line model a CS of 0.6 M⊙ which evolves more slowly. Model numbers refer to the above cited studies. Since MV increases with evolutionary time, the MV axis represents a (highly) nonlinear time axis: for MV < 4 the CS heats up towards its temperature maximum and the PN is optically thin. Differences for high excitation nebulae are most probably due to different helium abundances. When the rate of ionizing photons decreases as the nuclear energy sources extinguish (MV > 4), the excitation may decline, depending on the density in the nebula. For the so called “accreting models” (M > 10−6M⊙ α−1) the mass accretion from the AGB wind determines the density hence nebular excitation. For an AGB mass loss rate M < 10−5M⊙α−1 the numerical results approximately fit an exponential law E= E0exp (-M⊙) with E0 ≊ 1.1 and M⊙ ≊ 6.1 × 10−6M⊙ α−1. From the spread of the observed E(MV = 4) we conclude a mean AGB mass loss rate of 6.+3.3−2.3 10−6M⊙ α−1 within 1σ error bars. Obviously the model 11 reproduces the data best since most of the observed objects are found in the dark shadowed regions of the histogram. This is totally consistent with our previous results (cited above). The colliding-wind models, having no initially PN, behave quite similar as model 11.

scholarly journals Mass Loss Rates in Central Stars of Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 293-300 ◽  
Author(s):  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Central Star ◽  
Line Radiation ◽  
The Status ◽  
The Right ◽  
Central Stars ◽  
Loss Rates

Central stars of planetary nebulae (PNCS) frequently exhibit fast winds (cf. Cerruti-Sola and Perinotto, 1985; C.P. and Grewing, this volume). They may be important for the structure of the whole nebula as well as for the evolution of the central star. Their speed is typically two orders of magnitude higher than that of the classical optically visible nebula, which in turn expands a few times faster than the most external winds detected in few cases in the radio domain.I review here the status of art in the determination of the mass loss rates (M) associated with these fast winds. I restrict myself to the ‘observational’ determinations. Only at the end I will say something about the predictions of multi-scattering line radiation wind driven theory in connection with one best studied object: N6C 6543. This allows one to conclude that this theory may be the right explanation also for these winds.

scholarly journals Planetary Nebula Evolution Traced by Distance-Independent Parameters

1993 ◽  
Vol 155 ◽  
pp. 480-480
Author(s):  
C.Y. Zhang ◽  
S. Kwok
Keyword(s):  
Physical Properties ◽  
Mass Distribution ◽  
Planetary Nebula ◽  
Strong Support ◽  
Planetary Nebulae ◽  
Central Star ◽  
Evolution Model ◽  
The Core ◽  
Independent Parameters ◽  
Central Stars

Making use of the results from recent infrared and radio surveys of planetary nebulae, we have selected 431 nebulae to form a sample where a number of distance-independent parameters (e.g., Tb, Td, I60μm and IRE) can be constructed. In addition, we also made use of other distance-independent parameters ne and T∗ where recent measurements are available. We have investigated the relationships among these parameters in the context of a coupled evolution model of the nebula and the central star. We find that most of the observed data in fact lie within the area covered by the model tracks, therefore lending strong support to the correctness of the model. Most interestingly, we find that the evolutionary tracks for nebulae with central stars of different core masses can be separated in a Tb-T∗ plane. This implies that the core masses and ages of the central stars can be determined completely independent of distance assumptions. The core masses and ages have been obtained for 302 central stars with previously determined central-star temperatures. We find that the mass distribution of the central stars strongly peaks at 0.6 M⊙, with 66% of the sample having masses <0.64 MM⊙. The luminosities of the central stars are then derived from their positions in the HR diagram according to their core masses and central star temperatures. If this method of mass (and luminosity) determination turns out to be accurate, we can bypass the extremely unreliable estimates for distances, and will be able to derive other physical properties of planetary nebulae.

scholarly journals Characterizing global expansion evolution of the ionized matter in planetary nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 352-353
Author(s):  
J. A. López ◽  
M. G. Richer ◽  
M. Pereyra ◽  
M. T. García-Díaz
Keyword(s):  
Galactic Halo ◽  
Evolutionary Rate ◽  
Planetary Nebulae ◽  
Central Star ◽  
Global Expansion ◽  
Kinematic Evolution ◽  
Wide Range ◽  
Model Predictions ◽  
First Time ◽  
Highly Evolved

AbstractBulk outflow or global expansion velocities are presented for a large number of planetary nebulae (PNe) that span a wide range of evolutionary stages and different stellar populations. The sample comprises 133 PNe from the Galactic bulge, 100 mature and highly evolved PNe from the disk, 11 PNe from the Galactic halo and 15 PNe with very low central star masses and low metallicities, for a total of 259 PNe. These results reveal from a statistical perspective the kinematic evolution of the expansion velocities of PNe in relation to changing characteristics of the central star’s wind and ionizing luminosity and as a function of the evolutionary rate determined by the central (CS) mass. The large number of PNe utilized in this work for each group of PNe under study and the homogeneity of the data provide for the first time a solid benchmark form observations for model predictions, as has been described by López et al. (2016).

scholarly journals GLMP 160 – the first [WR] star in a binary

2011 ◽  
Vol 7 (S283) ◽  
pp. 382-383
Author(s):  
Marcin Hajduk ◽  
Peter A. M. van Hoof ◽  
Albert A. Zijlstra
Keyword(s):  
Binary System ◽  
Binary Systems ◽  
Central Star ◽  
Central Stars

AbstractWe discuss the results of the search for [WR] central stars in binary systems. GLMP 160 is the first [WR] central star in a binary system known. We analyze photometry, spectroscopy and imaging of this system.

scholarly journals Central Star and Nebular Masses for Magellanic Cloud Planetary Nebulae

1989 ◽  
Vol 131 ◽  
pp. 355-355 ◽  
Author(s):  
D. J. Monk ◽  
M. J. Barlow ◽  
R. E. S. Clegg
Keyword(s):  
Planetary Nebulae ◽  
Central Star ◽  
Magellanic Cloud ◽  
Effective Temperatures ◽  
Central Stars

AAT and IUE spectra of thirteen medium-excitation Magellanic Cloud planetary nebulae have been used to derive H I Zanstra effective temperatures and surface gravities for the central stars.

scholarly journals Searching for central stars of planetary nebulae in Gaia DR2

2020 ◽  
Vol 638 ◽  
pp. A103 ◽  
Author(s):  
N. Chornay ◽  
N. A. Walton
Keyword(s):  
Planetary Nebulae ◽  
Central Star ◽  
Ratio Method ◽  
Distance Measurements ◽  
Accurate Identification ◽  
Trigonometric Parallaxes ◽  
Model Independent ◽  
Statistical Distance ◽  
Automated Technique ◽  
Central Stars

Context. Accurate distance measurements are fundamental to the study of planetary nebulae (PNe) but they have long been elusive. The most accurate and model-independent distance measurements for galactic PNe come from the trigonometric parallaxes of their central stars, which were only available for a few tens of objects prior to the Gaia mission. Aims. The accurate identification of PN central stars in the Gaia source catalogues is a critical prerequisite for leveraging the unprecedented scope and precision of the trigonometric parallaxes measured by Gaia. Our aim is to build a complete sample of PN central star detections with minimal contamination. Methods. We developed and applied an automated technique based on the likelihood ratio method to match candidate central stars in Gaia Data Release 2 (DR2) to known PNe in the Hong Kong/AAO/Strasbourg Hα PN catalogue, taking into account the BP – RP colours of the Gaia sources as well as their positional offsets from the nebula centres. These parameter distributions for both true central stars and background sources were inferred directly from the data. Results. We present a catalogue of over 1000 Gaia sources that our method has automatically identified as likely PN central stars. We demonstrate how the best matches enable us to trace nebula and central star evolution and to validate existing statistical distance scales, and we discuss the prospects for further refinement of the matching based on additional data. We also compare the accuracy of our catalogue to that of previous works.

scholarly journals P Cygni profiles variability in central stars of Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 125-125
Author(s):  
P. Patriarchi ◽  
M. Perinotto
Keyword(s):  
Mass Loss ◽  
Planetary Nebulae ◽  
Associated Mass ◽  
Central Stars ◽  
Loss Rates

The variability of P Cygni profiles is important because of its connection with the mechanism of wind production and with the behaviour of the associated mass loss rates.

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