The Deceleration of Nebular Shells in Evolved Planetary Nebulae

Pereyra, Margarita; Richer, M. G.; López, J. A.

doi:10.1088/0004-637x/771/2/114

Cited by 19 publications

(45 citation statements)

References 34 publications

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“…We adhere to our argument that such decelerations are either only apparent due to ionisation stratification or, if indeed real, only a transient phenomenon: flow speeds can be reduced during a possible phase of recombination, but quickly recover former expansion rates once re-ionisation sets in. Regarding the hint of Pereyra et al (2013) that experiencing a possible interaction with the interstellar matter (ISM) might be another source for PN deceleration, it seems worthwhile to correlate velocity studies such as our and Pereyra et al with the statistical studies on PNe-ISM interaction, e.g., Ali et al (2012, A&A 541, A98). Table A.1 contains the detailed information about all the objects considered in the present study.…”

Section: Moementioning

confidence: 78%

“…The recently published paper of Pereyra et al (2013) reported a deceleration of nebular expansion in evolved PNe. Peak-separation velocity data of PNe which are in common in both studies agree for the most part.…”

Section: Moementioning

confidence: 96%

“…We note that their sample is not volume-limited. The 2-kpc sample of our Table A.1 could be increased by 8 (out of 100) objects from Pereyra et al (2013). Unfortunately, combining the velocity information of both studies yields only two additional PNe for which then both [N ii] and [O iii] velocities are available, viz.…”

Section: Moementioning

confidence: 99%

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The evolution of planetary nebulae

Jacob

Schönberner

Steffen

2013

A&A

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Context. The visibility time of planetary nebulae (PNe) in stellar systems is an essential quantity for estimating the size of a PN population in the context of general population studies. For instance, it enters directly into the PN death rate determination. Aims. The basic ingredient for determining visibility times is the typical nebular expansion velocity, as a suited average over all PN sizes of a PN population within a certain volume or stellar system. The true expansion speed of the outer nebular edge of a PN is, however, not accessible by spectroscopy -a difficulty that we surmount by radiation-hydrodynamics modelling. Methods. We first discuss the definition of the PN radius and possible differences between the observable PN radius and its physical counterpart, the position of the leading shock of the nebular shell. We also compare the Hα surface-brightness evolution predicted by our radiation-hydrodynamics models with the recent Hα surface-brightness radius calibration of Frew (2008, Ph.D. Thesis, Macquarie University, Australia) and find excellent agreement. We then carefully investigate the existing spectroscopic data on nebular expansion velocities for a local PN sample with objects up to a distance of 2 kpc with well-defined round/elliptical shapes. We evaluate, by means of our radiation-hydrodynamics models, how these observed expansion velocities must be corrected in order to get the true expansion speed of the outer nebular edge. Results. We find a mean true expansion velocity of 42 km s −1 , i.e. nearly twice as high as the commonly adopted value to date. Accordingly, the time for a PN to expand to a radius of, say 0.9 pc, is only 21 000 ± 5000 years. This visibility time of a PN holds for all central star masses since a nebula does not become extinct as the central star fades. There is, however, a dependence on metallicity in the sense that the visibility time becomes shorter for lower nebular metal content. Conclusions. These statements on the visibility time only hold for volume-limited samples. Extragalactic samples that contain spatially unresolved nebulae are flux limited, and in this case the visibility time directly depends on the limiting magnitude of the survey. To reach a visibility time of 21 000 years, the survey must reach about 7 mag below the bright cut-off of the planetary nebula luminosity function. With the higher expansion rate of PNe derived here we determined their local death-rate density as (1.4 ± 0.5) × 10 −12 PN pc −3 yr −1 , using the local PN density advocated by .

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Section: Moementioning

confidence: 78%

Section: Moementioning

confidence: 96%

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The evolution of planetary nebulae

Jacob

Schönberner

Steffen

2013

A&A

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“…We suggest that the object needs to be reclassified. Images of this object are found in Pereyra et al (2013) PN G226.7+05.6: all authors agree that the object shows a bipolar morphology. Stanghellini et al (1993b) classified it as bipolar with an outer structure.…”

Section: Notes On Individual Objectsmentioning

confidence: 75%

Atlas of monochromatic images of planetary nebulae

Weidmann

Schmidt

Valdarenas

et al. 2016

A&A

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“…The sample is broadly divided into two groups, namely, mature PNe that still show some structure and bright outer edges but no rim and highly evolved PNe with low surface brightness and no inner structure. The detailed results of the study of these groups have appeared in [20]. There are 100 PNe in this group, 22 of them are considered mature and 78 highly evolved.…”

Section: The Mature and Highly Evolved Pne Samplementioning

confidence: 99%

The kinematic evolution of the ionized shells of planetary nebulae

López¹,

Richer²,

Pereyra

et al. 2016

J. Phys.: Conf. Ser.

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Abstract. In this contribution we present the results of measuring the bulk outflow, or global expansion velocities 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. The long-slit, echelle data are drawn from the SPM Kinematic Catalogue of Galactic Planetary Nebulae. These results reveal from a statistical perspective the kinematic evolution of the expansion velocities of PNe in relation with the changing characteristics of the central star's wind and ionizing luminosity and as a function of the evolutionary rate determined by the central star (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 from observations for models predictions. This project is still in progress and aims at measuring expansion velocities for about 300 more galactic PNe with the aim of providing a reliable parametric description of their expansion velocity in terms of different populations, morphologies, evolutionary stages and CS masses. IntroductionPlanetary Nebulae are expanding ionized shells evolving from the mass loss process in the previous AGB stage. The expanding nature of PNe was recognized nearly 70 years ago [1]. It was then inferred [2] that PNe should descend from fast-evolving, mass-losing red giant stars to eventually become white dwarfs. These ideas led to the concept of PNe originating in the ejected envelope of red giants [3] and shortly after the first basic post-AGB evolutionary model track was calculated [4] starting with an AGB star with an electron degenerate core and a H shell burning envelope. The times were ripe to realize then that the AGB envelope is the precursor of the PN [5]. However, the shells of AGB stars need additional pressure to keep an expanding motion after being ejected and various mechanisms involving ionization fronts and radiation pressure on gas and dust were explored with unsatisfactory results, until it was concluded [6] that mass loss from active stellar winds was needed to maintain the shell expansion. This problem was originally solved through the interacting stellar winds model (ISW) [7] [8] where after the initial AGB mass loss phase the exposed core of the now much smaller star becomes hotter and mass loss through radiation pressure develops a faster wind that interacts with the previous slower wind from the AGB producing a shocked interface between the two. The ISW model provides

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The Deceleration of Nebular Shells in Evolved Planetary Nebulae

Cited by 19 publications

References 34 publications

The evolution of planetary nebulae

The evolution of planetary nebulae

Atlas of monochromatic images of planetary nebulae

The kinematic evolution of the ionized shells of planetary nebulae

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