Physical Properties of the Central Stars of Planetary Nebulae in the Magellanic Clouds

Absolute flux distributions in the ultraviolet continua of the central stars of three planetary nebulae of known distances have been derived from observations made with the International Ultraviolet Explorer. The observations confirm the existence of planetary nebulae nuclei with masses of ≈1M⊙ and indicate that the progenitors of the nebulae were carbon stars near the theoretical upper luminosity threshold of Mbol = −6.5. The derived masses, luminosities, and temperatures of the three stars indicate that they are currently on horizontal tracks in the HR diagram and probably have not yet attained their maximum luminosities. The present luminosities (≈ 4 × 104 L⊙) each are well above the Eddington luminosity for an 0.6 Mo star. The derived properties of the stars and associated nebulae (LMC P40, SMC N2, SMC N5) are consistent with a nebular ejection mechanism that involves radiation pressure on carbon grains.

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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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Planetary Nebulae in the Magellanic Clouds

Symposium - International Astronomical Union ◽

10.1017/s0074180900118145 ◽

1999 ◽

Vol 190 ◽

pp. 332-338 ◽

Cited By ~ 1

Author(s):

Michael A. Dopita

Keyword(s):

Hubble Space Telescope ◽

Morphological Structure ◽

Planetary Nebulae ◽

Spectroscopic Studies ◽

Magellanic Clouds ◽

Star Formation History ◽

Formation History ◽

History Of ◽

Central Stars ◽

The Ideal

The proximity, accurately known distance and low line-of-sight reddening give the ideal circumstances to pursue studies of individual stellar populations in the Magellanic Clouds. Here we show how our understanding of the evolution and chemical composition of the planetary nebulae in the Magellanic Clouds has been impacted by imaging and UV spectroscopic studies using the Hubble Space Telescope. Images provide sizes, internal morphological structure, absolute fluxes, and dynamical ages, while spectra allow us to place the central stars accurately on the H-R Diagram, and we can also examine the details of the evolution, of mass- and age- dependent chemical dredge-up processes, and infer the star-formation history of the Magellanic Clouds.

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The role of heat conduction to the formation of [WC]-type planetary nebulae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312012094 ◽

2011 ◽

Vol 7 (S283) ◽

pp. 494-495

Author(s):

Christer Sandin ◽

Matthias Steffen ◽

Ralf Jacob ◽

Detlef Schönberner ◽

Ute Rühling ◽

...

Keyword(s):

Heat Conduction ◽

Chemical Composition ◽

Physical Properties ◽

Planetary Nebulae ◽

Time Dependent ◽

Diffuse Emission ◽

Hydrodynamic Models ◽

X Ray ◽

Central Stars

AbstractX-ray observations of young Planetary Nebulæ (PNe) have revealed diffuse emission in extended regions around both H-rich and H-deficient central stars. In order to also reproduce physical properties of H-deficient objects, we have, at first, extended our time-dependent radiation-hydrodynamic models with heat conduction for such conditions. Here we present some of the important physical concepts, which determine how and when a hot wind-blown bubble forms. In this study we have had to consider the, largely unknown, evolution of the CSPN, the slow (AGB) wind, the fast hot-CSPN wind, and the chemical composition. The main conclusion of our work is that heat conduction is needed to explain X-ray properties of wind-blown bubbles also in H-deficient objects.

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X-ray Observations of Planetary Nebulae since WORKPLANS I and Beyond

Galaxies ◽

10.3390/galaxies8010024 ◽

2020 ◽

Vol 8 (1) ◽

pp. 24

Author(s):

Martín A. Guerrero

Keyword(s):

Physical Properties ◽

Planetary Nebulae ◽

X Ray ◽

Central Stars

Planetary nebulae (PNe) were expected to be filled with hot pressurized gas driving their expansion. ROSAT hinted at the presence of diffuse X-ray emission from these hot bubbles and detected the first sources of hard X-ray emission from their central stars, but it was not until the advent of Chandra and XMM-Newton that we became able to study in detail their occurrence and physical properties. Here I review the progress in the X-ray observations of PNe since the first WORKshop for PLAnetary Nebulae observationS (WORKPLANS) and present the perspective for future X-ray missions with particular emphasis on eROSITA.

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Planetary nebulae in the VISTA Magellanic Cloud (VMC) Survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312011842 ◽

2011 ◽

Vol 7 (S283) ◽

pp. 444-445

Author(s):

Brent Miszalski ◽

Ralph Napiwotzki ◽

Maria-Rosa L. Cioni ◽

Martin A. T. Groenewegen ◽

Jose M. Oliveira ◽

...

Keyword(s):

Luminosity Function ◽

Near Infrared ◽

Planetary Nebulae ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Magellanic Clouds ◽

First Year ◽

Complementary Role ◽

Initial Results ◽

Central Stars

AbstractThe multi-epoch YJKs sub-arcsecond photometry of the VMC survey provides a long anticipated deep near-infrared (NIR) window into further understanding the stellar populations of the Magellanic Clouds. The first year of observations consisted of six tiles covering ~9% of the Large Magellanic Cloud (LMC) survey region and contains 102 objects previously classified as planetary nebulae (PNe). A large proportion of the sample were found to be contaminated by non-PNe. These initial results underline the importance of establishing a clean catalogue of LMC PNe before they are applied in areas such as the planetary nebula luminosity function (PNLF) and searches for binary central stars. As the VMC survey progresses it will play a fundamental role in cleaning extant PN catalogues and a complementary role in the discovery of new PNe.

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Rapid evolution of [WC] stars in the Magellanic Clouds

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038049 ◽

2020 ◽

Vol 642 ◽

pp. A71

Author(s):

Marcin Hajduk

Keyword(s):

South African ◽

Rapid Evolution ◽

Planetary Nebulae ◽

Magellanic Clouds ◽

Asymptotic Giant Branch ◽

Asymptotic Giant Branch Stars ◽

Evolutionary Models ◽

Heating Rates ◽

Giant Branch Stars ◽

Central Stars

We obtained new spectra of fourteen Magellanic Cloud planetary nebulae with the South African Large Telescope to determine heating rates of their central stars and to verify evolutionary models of post-asymptotic giant branch stars. We compared new spectra with observations made in previous years. Five planetary nebulae showed an increase in excitation over time. Four of their central stars exhibit [WC] features in their spectra, including three new detections. This raises the total number of [WC] central stars of PNe in the Magellanic Clouds to ten. We compared determined heating rates of the four [WC] central stars with the He-burning post-asymptotic giant branch evolutionary tracks and the remaining star with the H-burning tracks. Determined heating rates are consistent with the evolutionary models for both H and He-burning post-asymptotic giant branch stars. The central stars of the PNe that show the fastest increase of excitation are also the most luminous in the sample. This indicates that [WC] central stars in the Magellanic Clouds evolve faster than H-burning central stars, and they originate from more massive progenitors.

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