Close Binaries and the Abundance Discrepancy Problem in Planetary Nebulae

Motivated by the recent establishment of a connection between central star binarity and extreme abundance discrepancies in planetary nebulae, we have carried out a spectroscopic survey targeting planetary nebula with binary central stars and previously unmeasured recombination line abundances. We have discovered seven new extreme abundance discrepancies, confirming that binarity is key to understanding the abundance discrepancy problem. Analysis of all 15 objects with a binary central star and a measured abundance discrepancy suggests a cut-off period of about 1.15 days, below which extreme abundance discrepancies are found.

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Planetary Nebula Evolution Traced by Distance-Independent Parameters

Symposium - International Astronomical Union ◽

10.1017/s0074180900172134 ◽

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.

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The Photographic Observations of Some Planetary Nebulae

Symposium - International Astronomical Union ◽

10.1017/s0074180900170032 ◽

1993 ◽

Vol 155 ◽

pp. 41-41

Author(s):

Xiangliang Hao

Keyword(s):

Planetary Nebula ◽

Planetary Nebulae ◽

Central Star ◽

Processing Method ◽

Primary Research ◽

Temperature Changes ◽

Long Period ◽

The Earth ◽

Long Time ◽

Central Stars

The first planetary nebula was discovered by Messier in 1794. But for some reasons it has not been studied detail for a long time, especially for the central star Of planetary nebula. The primary research for these objects showed that the lifetime of a planetary nebula is about 5 104 years, but in this period the luminosity of central star varies from 63 L⊙ to nearly 3.5 104L⊙ and then decrease to 100 L⊙; its temperature changes from 3.4 104 to 105K and then begins to decrease (Seaton 1966). The radius of central stars also have fast varies in planetary nebula phase. For these reasons we consider that in the planetary nebula phase the activities of central star is very drastic and the result of these activities must cause some variation at the surface of central star witch may be detected on the earth, especially for the surface light variations. Some observers have been trying to find the luminosity variations in central stars. But until now no one has made systematical survey for these. Since the different authors used different instruments amd different processing methods at different places which may be caused a lot of uncertainty in the photometry of planetary nebulae and central stars. So it is hard to decide whether the differences between the authors or the essential variations of the objects is responsible of the observing differences. Therefore, we have selected over fifty planetary nebulae to observe for a long period at Beijing Observatory using the same instrument and the same processing method. From these observations we may determine the light variations and the brightness of the planetary nebulae and central stars more correctly.

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Recombination line abundances in the winds of the [WC] Wolf-Rayet stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900130001 ◽

1997 ◽

Vol 180 ◽

pp. 112-113

Author(s):

R. L. Kingsburgh ◽

I. Dashevsky ◽

M. J. Barlow

Keyword(s):

Stellar Wind ◽

Planetary Nebulae ◽

Central Star ◽

Emission Lines ◽

Early Type ◽

Recombination Line ◽

Optical Spectrophotometry ◽

Central Stars ◽

Line Analysis

We present a preliminary abundance analysis, utilising recombination theory, for the [WC] Wolf-Rayet central stars of the planetary nebulae NGC 6751 and NGC 6905. This analysis is based on optical spectrophotometry of a sample of [WC] stars which show a strong O vi 3811, 34 å feature in emission. We have performed a recombination line analysis of stellar wind emission lines which are judged to be optically thin, in order to derive relative C, O and He abundances. We also present a comparison of the derived wind abundances with those of Population I WO stars. For the [WC 4] central star of NGC 6751, we have derived C/He = 0.35 and C/O = 4.2, by number. And for the [WC 3] central star of NGC 6905, we have derived C/He = 0.36 and C/O< 12. These surface abundances are comparable to the abundances that have been derived for early type [WC] stars via more complex NLTE modelling (e.g. Koesterke & Hamann 1996).

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Mass loss from central stars of planetary nebulae

International Astronomical Union Colloquium ◽

10.1017/s0252921100094562 ◽

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.

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Nonradial Pulsational Analyses of the Pulsating Central Stars of Planetary Nebulae

Symposium - International Astronomical Union ◽

10.1017/s0074180900138598 ◽

1989 ◽

Vol 131 ◽

pp. 311-311

Author(s):

Sumner Starrfield ◽

Arthur N. Cox

Keyword(s):

Planetary Nebula ◽

Spectral Characteristics ◽

Planetary Nebulae ◽

Central Star ◽

Nonradial Pulsation ◽

Central Stars

We have performed nonradial pulsation analyses of the central star of the planetary nebula K1-16. K1-16 is a very unusual nebulae which appears to have ejected material that is very rich in helium. The central star shows no evidence for hydrogen in its spectrum and the helium and carbon lines are in emission. Grauer and Bond (Ap. J., 277, 211, 1984) discovered that it is pulsating with periods around 1700 sec. Although its spectral characteristics are similar to those of the PG1159-035 variables, it is pulsating in much longer periods than they are.

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The Binary Central Star of Hf 38

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317000485 ◽

2016 ◽

Vol 12 (S323) ◽

pp. 382-383

Author(s):

Helen Barker

Keyword(s):

Planetary Nebula ◽

Galactic Plane ◽

Planetary Nebulae ◽

Central Star ◽

Using Data ◽

The Impact ◽

Initial Results ◽

Central Stars

AbstractDespite years of effort, the impact of central star binarity on planetary nebula formation and shaping remains unclear. This is hampered by the fact that detecting central star binarity is inherently difficult, and requires very precise observations. The fraction of planetary nebulae with binary central stars therefore remains elusive. This work presents initial results of central star analysis using data from the VST Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+). The true central star of PN Hf 38 has been revealed, and it exhibits a 0.465±0.334 i band magnitude excess, indicative of a M0V companion.

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Surveying Planetary Nebulae Central Stars for Close Binaries: Constraining Evolution of Central Stars Based on Binary Parameters

Galaxies ◽

10.3390/galaxies6030085 ◽

2018 ◽

Vol 6 (3) ◽

pp. 85 ◽

Cited By ~ 2

Author(s):

Todd Hillwig

Keyword(s):

Binary Stars ◽

Planetary Nebula ◽

Planetary Nebulae ◽

Close Binary ◽

Close Binaries ◽

Common Envelope ◽

Close Binary Stars ◽

Red Giant ◽

The Relationship ◽

Central Stars

The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship between the proto-planetary nebula and planetary nebula stages, demonstrating that the known proto-planetary nebulae are not the precursors of planetary nebulae with close binary central stars.

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The Formation of Planetary Nebulae with Close Binary Nuclei

Symposium - International Astronomical Union ◽

10.1017/s0074180900065529 ◽

1980 ◽

Vol 88 ◽

pp. 571-573

Author(s):

J. Saltzman ◽

M. Livio ◽

G. Shaviv

Keyword(s):

Planetary Nebula ◽

Planetary Nebulae ◽

Close Binary ◽

Close Binaries ◽

Central Stars

Recent observations of nuclei of planetary nebula have shown that some of the central stars are binaries and even close binaries with periods of hours to few days.

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O VI Central Stars of Planetary Nebulae: NGC 2371

Symposium - International Astronomical Union ◽

10.1017/s0074180900172250 ◽

1993 ◽

Vol 155 ◽

pp. 492-492

Author(s):

L. Stanghellini ◽

J.B. Kaler ◽

R.A. Shaw

Keyword(s):

Planetary Nebula ◽

Planetary Nebulae ◽

Central Star ◽

The Other ◽

Evolutionary Sequence ◽

Stellar Pulsation ◽

Fast Wind ◽

Near Future ◽

Broad Feature ◽

Central Stars

We performed detailed spectral analysis of the planetary nebula NGC 2371 and its nucleus. The central star of NGC 2371 is a member of the 0 VI PNNi class, and it shows luminosity variations (Bond & Ciardullo 1990, ASP Conf. Ser. vol 11, Confrontation between Stellar Pulsation and Evolution, C. Cacciari & G. Clementini (eds.), p. 529) that could be associated to nonradial pulsations. From the spectrum of NGC 2371 we calculate the nebular parameters and the abundance of the most prominent ions. The nucleus is hot (Teff ≥ 120,000K) and luminous (V=15.4), it is probably close to the blue bend of the post-AGB evolutionary sequence, and shows prominent O VI emission with (so far) unique double narrow-broad feature, as shown in the Figures. This feature can not be related to the shock front of the fast wind into the planetary nebula. This star has been analyzed together with the other O VI PNNi known. A preliminary correlation between the stellar parameters and the total O VI strength have been derived, and the locus of NGC 2371 on the logTeff – logL/L⊙ plane have been studied in relation to the locus of the post-AGB nonradial instability strips. These results, together with a study on the other O VI central stars of planetary nebulae, will be published in the near future.

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Spectroscopy of the central stars of three old Planetary Nebulae

Symposium - International Astronomical Union ◽

10.1017/s0074180900130153 ◽

1997 ◽

Vol 180 ◽

pp. 133-133

Author(s):

W. Saurer ◽

K. Werner ◽

R. Weinberger

Keyword(s):

Transition Region ◽

White Dwarf ◽

Planetary Nebula ◽

Planetary Nebulae ◽

Central Star ◽

Limited Sample ◽

Central Stars

The knowledge of the planetary nebula central star - white dwarf transition region has dramatically increased during the most recent years and dozens of stars now populate this former gap in the HRD. Each addition to the limited sample of central stars that has been studied spectroscopically in detail is, however, of value.

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