Post-AGB Stars

Waelkens, Christoffel; Waters, Rens

doi:10.1007/978-1-4757-3876-6_10

Cited by 8 publications

(9 citation statements)

References 126 publications

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“…In defining criteria, we have been inspired by the precepts introduced by Kwok (1993), Van Winckel (2003) and Waelkens & Waters (2004). We emphasize that with the established criteria we have tried to cover all stellar objects classified for various reasons as post-AGB 2 .…”

Section: Classification Criteriamentioning

confidence: 99%

An evolutionary catalogue of galactic post-AGB and related objects

Szczerba¹,

Siódmiak

Stasińska

et al. 2007

A&A

132

169

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Aims. With the ongoing AKARI infrared sky survey, of much greater sensitivity than IRAS, a wealth of post-AGB objects may be discovered. It is thus time to organize our present knowledge of known post-AGB stars in the galaxy with a view to using it to search for new post-AGB objects among AKARI sources. Methods. We searched the literature available on the NASA Astrophysics Data System up to 1 October 2006, and defined criteria for classifying sources into three categories: very likely, possible and disqualified post-AGB objects. The category of very likely post-AGB objects is made up of several classes. Results. We have created an evolutionary, on-line catalogue of Galactic post-AGB objects, to be referred to as the Toruń catalogue of Galactic post-AGB and related objects. The present version of the catalogue contains 326 very likely, 107 possible and 64 disqualified objects. For the very likely post-AGB objects, the catalogue gives the available optical and infrared photometry, infrared spectroscopy and spectral types, and links to finding charts and bibliography.

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Section: Classification Criteriamentioning

confidence: 99%

An evolutionary catalogue of galactic post-AGB and related objects

Szczerba¹,

Siódmiak

Stasińska

et al. 2007

A&A

132

169

View full text Add to dashboard Cite

show abstract

“…8 the colour variations and the light variations are folded on the same period. As was noted by Waelkens & Burnet (1985), the U − B and B − V variations are respectively in antiphase and in phase with the light variations. This result is important in the discussion of the pulsational nature of HD 190390 (Sects.…”

Section: Light Curves and Colour Variationsmentioning

confidence: 96%

“…Fernie (1986) published an analysis based on 32 observations in the uvbyβ(RI) system and mentions a range in the y magnitude of 0.3 mag and a possible period of 28.4 or 11.8 days. At nearly the same time, Waelkens & Burnet (1985) presented their frequency analysis of 123 measurements in the Geneva photometric system (Rufener 1981), obtained with the Swiss photometric telescope at the European Southern Observatory. The data covered 1040 days and revealed a most significant period of 28.49 days, accounting for 80% of the total variance.…”

Section: Variability Analysismentioning

confidence: 99%

“…Given its low metal content already mentioned by McDonald (1976) and its high galactic latitude, HD 190390 was mentioned as a possible UU Her candidate (Waelkens & Burnet 1985;Sasselov 1985;Fernie 1986). However, due to the apparently stable and short period (relative to other UU Her candidates) found by Waelkens & Burnet, the genuine character of HD 190390 as UU Her star was doubted.…”

Section: Uu Her Classificationmentioning

confidence: 99%

“…Waelkens & Burnet (1985) and Fernie (1986). This variablity made HD 190390 a candidate member of the UU Her type stars, a heterogeneous class of luminous variables at high galactic latitudes defined by Sasselov (1984), which also includes 89 Her and HD 161796.…”

Section: Introductionmentioning

confidence: 99%

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The evolutionary status of the bright high-latitude supergiant HD 190390

Reyniers

Cuypers

2005

A&A

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Abstract. Despite its mean apparent magnitude of m V = 6.39, the evolutionary status of HD 190390 (HR 7671), a luminous F-type supergiant at high galactic latitude, is still not very clear, but in most papers a post-AGB classification is assumed. New observational material has been obtained with four different instruments and is presented here. An extensive abundance analysis based on high resolution, high signal-to-noise NTT+EMMI spectra confirms the metal deficiency of this object ([Fe/H] = −1.6), together with a high lithium content (log (Li) = 1.9). A variability analysis based on Geneva photometry over seven years reveals beating with a period of ∼3000 days. It is, however, not clear whether this beating is caused by a stable triplet, or it is the consequence of small changes in the main frequency. More recent data obtained with the HIPPARCOS satellite and the Mercator telescope not only confirm the main period, but also support the presence of a second periodicity of 11 days, which was also found in the Geneva photometry. A conclusive evolutionary status of this object is not given, but alternative to the UU Her (i.e. post-AGB) status, a W Vir classification is discussed.

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Shaping Bipolar Planetary Nebulae: How Mass Loss Leads to Waistline Development

Dijkstra

Speck

2006

ApJ

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Asymptotic Giant Branch (AGB) stars generally have spherically symmetric envelopes, whereas most post-AGB stars and Planetary Nebulae (PNe) show axisymmetric circumstellar envelopes. While various mechanisms for axisymmetric circumstellar structures may explain the shapes of PNe, they do not address how the shape of the circumstellar shell evolves. Here we address the temporal changes in the axisymmetry of AGB star envelopes, and in particular the development of the torus required in the Generalized Interacting Stellar Winds (GISW) model. Assuming (1) an AGB star rotates with sufficient angular speed at the start of the AGB phase; and (2) that the rotational angular momentum of the AGB star is conserved, we demonstrate that some very important observational features of AGB star axisymmetry evolution can be reproduced. We find that, compared to the star's increasing luminosity and decreasing effective temperature, the decreasing mass of the star primarily affects the axisymmetry of the envelope. When a representative mass loss history is adopted, where most of the mass is lost near the end of the AGB phase, the envelope's axisymmetry increases over time, with the strongest increase occurring near the end of the AGB phase. This may naturally explain why most AGB stars have spherically symmetric envelopes, while axisymmetry seems common-place in the post-AGB/PNe phase. The degree of axisymmetry at the end of the AGB phase is found to increase with increasing main sequence mass, and the onset of axisymmetry occurs only after the onset of the superwind (SW) phase, in good agreement with the observations.

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Post-AGB Stars

Cited by 8 publications

References 126 publications

An evolutionary catalogue of galactic post-AGB and related objects

An evolutionary catalogue of galactic post-AGB and related objects

The evolutionary status of the bright high-latitude supergiant HD 190390

Shaping Bipolar Planetary Nebulae: How Mass Loss Leads to Waistline Development

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