The post-AGB evolution of AGB mass loss variations

Meijerink, R.; Mellema, Garrelt; Simis, Yvonne

doi:10.1051/0004-6361:20030696

Cited by 12 publications

(12 citation statements)

References 22 publications

(48 reference statements)

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“…Garcia‐Segura, Lopez & Franco (2001), on the other hand, point out that where there are changes in the polarity of the progenitor magnetic field, and where the stellar wind is also magnetized, then this would lead to pressure oscillations which drive circularly symmetric compressions into the outflowing winds. Their results are startlingly similar to those observed for He 2−90, although it has been suggested that the magnetic dynamo cycle in AGB stars would be much shorter than that corresponding to the rings (Meijerink et al 2003).…”

Section: Introductionsupporting

confidence: 75%

“…This leads to appreciable changes in the pressure and density characteristics of these regimes, and wipes out much of the evidence relating to later phases of AGB mass loss (e.g. Meijerink et al 2003;Perinotto et al 2004;Schönberner et al 2005, Mellema 1994).…”

Section: Introductionmentioning

confidence: 79%

“…Thus for instance, Simis, Icke & Dominik (2001) and Meijerink, Mellema & Simis (2003) have analysed viscous momentum coupling between outflowing gas and dust; an analysis in which dust grains are permitted to drift with respect to the neutral AGB envelope. The results show that spherically symmetric regions will develop in which dust-togas ratios are enhanced, and lead to results which are closely similar to those observed in young PNe.…”

Section: Introductionmentioning

confidence: 99%

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Rings and haloes in the mid-infrared: the planetary nebulae NGC 7354 and NGC 3242

Phillips¹,

Ramos-Larios²,

Schröder

et al. 2009

Monthly Notices of the Royal Astronomical Society

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We present images of the planetary nebulae NGC 7354 and NGC 3242 in four mid‐infrared (MIR) photometric bands centred at 3.6, 4.5, 5.8 and 8.0 μm, the results of observations undertaken using the Spitzer Space Telescope. The resulting images show the presence of a halo and rings in NGC 3242, as previously observed through narrow‐band imaging at visual wavelengths, as well as evidence for a comparable halo and ring system in NGC 7354. This is the first time that a halo and rings have been observed in the latter source. Similarly, whilst partial rings may have been previously detected in the MIR (for the source NGC 3132), the present observations appear to constitute the first detections of complete ring systems outside of the visual wavelength regime. The halo/core emission ratios appear to be preferentially higher at MIR wavelengths than is the case in the visible, and show less steep fall‐offs than those observed in the [O iii]λλ4959+ 5007 Å transitions. The variation in surface brightness S with radial distance R, where this is approximated by the power‐law relation S∝R−β, implies exponents 1.7 < β < 4 in the inner portions of the haloes, and 4.5 < β < 12 towards the outer limits of these structures. The value of β is also, in most cases, somewhat smaller at longer wavelengths. It is additionally noted that the 3.6 μm/4.5 μm, 5.8 μm/4.5 μm and 8.0 μm/4.5 μm flux ratios increase markedly away from the nuclei, and reach their maximum values in the haloes, where much of the longer wave flux may derive from dust band and continuum emission. An analysis of the rings suggests that some of them, at least, are likely to be associated with higher densities of dust particles, and that the gaseous and particle ring systems are likely to be spatially in register. Finally, we have analysed the formation of haloes as a result of radiatively accelerated mass loss in the AGB progenitors. Although the models assume that dust formation occurs in C‐rich environments, we note that qualitatively similar results would be expected for O‐rich progenitors as well. The model fall‐offs in halo density are found to result in gradients in halo surface brightness which are similar to those observed in the visible and MIR.

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Section: Introductionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Rings and haloes in the mid-infrared: the planetary nebulae NGC 7354 and NGC 3242

Phillips¹,

Ramos-Larios²,

Schröder

et al. 2009

Monthly Notices of the Royal Astronomical Society

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“…Neither the morphology at different spatial scales nor the motions detected very close to the center can be satisfactory explained by current models on the mass-loss mechanisms in AGB stars and their typical time-scales. For instance, Sandin & Höfner (2004 and references therein) have predicted shell density distributions not compatible with those observed around IRC+10216 (see also on the same topic Meijerink et al, 2003). Another scenario for the formation of the shells in a spherically symmetric stellar wind has been explored by Soker (2000Soker ( , 2002.…”

Section: Discussionmentioning

confidence: 99%

The circumstellar envelope of IRC+10216 from milli-arcsecond to arcmin scales

Leão

Laverny

Mékarnia

et al. 2006

A&A

104

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Aims. Analysis of the innermost regions of the carbon-rich star IRC+10216 and of the outer layers of its circumstellar envelope have been performed in order to constrain its mass-loss history. Methods. We analyzed the high dynamic range of near-infrared adaptive optics and the deep V-band images of the circumstellar envelope of IRC+10216 using high angular resolution, collected with the VLT/NACO and FORS1 instruments. Results. From the near-infrared observations, we present maps of the sub-arcsecond structures, or clumps, in the innermost regions. The morphology of these clumps is found to strongly vary from J-to L-band. Their relative motion appears to be more complex than proposed in earlier works: they can be weakly accelerated, have a constant velocity, or even be motionless with respect to one another. From V-band imaging, we present a high spatial resolution map of the shell distribution in the outer layers of IRC+10216. Shells are resolved well up to a distance of about 90 to the core of the nebula and most of them appear to be composed of thinner elongated shells. Finally, by combining the NACO and FORS1 images, a global view is present to show both the extended layers and the bipolar core of the nebula together with the real size of the inner clumps. Conclusions. This study confirms the rather complex nature of the IRC+10216 circumstellar environment. In particular, the coexistence at different spatial scales of structures with very different morphologies (clumps, bipolarity, and almost spherical external layers) is very puzzling. This confirms that the formation of AGB winds is far more complex than usually assumed in current models.

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“…In the current decade, thanks to the operations of high--sensitivity millimeter/submillimeter telescopes (e.g., ALMA, JVLA), the new detection of such patterns and their theoretical understanding have led to significant and synergistic progress. the patterns disappearing within ∼ 3000 years after ionization starts (Meijerink et al 2003). With the relevant model development (see §2) and the timescales consistent with the orbital periods of wide binaries, it is now commonly accepted that binary companions are responsible for modulating the mass distribution of CSEs in the recurrent form.…”

Section: Introductionmentioning

confidence: 96%

Circumstellar spirals/shells/arcs: the message from binary stars

Kim

2016

Proc. IAU

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A consensus has grown in the past few decades that binarity is key to understanding the morphological diversities of the circumstellar envelopes (CSEs) surrounding stars in the Asymptotic Giant Branch (AGB) to Planetary Nebula (PN) phase. The possible roles of binaries in their shaping have, however, yet to be confirmed. Meanwhile, recurrent patterns are often found in the CSEs of AGB stars and the outer halos of PNe, providing a fossil record of the mass loss during the AGB phase. In this regard, recent molecular line observations using interferometric facilities have revealed the spatio-kinematics of such patterns. Numerical simulations of binary interactions producing spiral-shells have been extensively developed, revealing new probes for extracting the stellar and orbital properties from these patterns. I review recent theoretical and observational investigations on the circumstellar spiral-shell patterns and discuss their implications in linking binary properties to the asymmetric ejection events in the post-AGB phase.

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The post-AGB evolution of AGB mass loss variations

Cited by 12 publications

References 22 publications

Rings and haloes in the mid-infrared: the planetary nebulae NGC 7354 and NGC 3242

Rings and haloes in the mid-infrared: the planetary nebulae NGC 7354 and NGC 3242

The circumstellar envelope of IRC+10216 from milli-arcsecond to arcmin scales

Circumstellar spirals/shells/arcs: the message from binary stars

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