The Evolution of the Kinematics of Nebular Shells in Planetary Nebulae in the Milky Way Bulge

Richer, M. G.; López, J. A.; García-Díaz, Ma. T.; Clark, David M.; Pereyra, Margarita; Díaz-Méndez, E.

doi:10.1088/0004-637x/716/1/857

Cited by 25 publications

(48 citation statements)

References 52 publications

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“…Despite of the small inconsistency between the velocities derived from our (unresolved) theoretical line profiles and those measured by Richer et al (2009Richer et al ( , 2010a, the interpretation of Fig. 37 is not really affected: we see how the ionisation stratification develops with time (or velocity) in nebular structures with positive velocity gradients in the same way as appropriate hydrodynamical models predict.…”

Section: Expansion Propertiessupporting

confidence: 43%

“…− 3.5, and their eye-estimated mean V HWHM is 18 km s −1 . Richer et al (2010b) argued again that the mean 5007 Å line width is not dependent upon maximum [O iii] luminosity, metallicity or age of the progenitor population. All these findings are well explained by our hydrodynamical models, especially by the 0.625 M sequences (Fig.…”

Section: Expansion Propertiesmentioning

confidence: 97%

“…4 in Richer (2006) and contains also the same data from different galaxies and/or parts of them. All the relevant data are now also available from Richer et al (2010b). The theoretical tracks of our two most massive central stars (0.696 and 0.625 M ) surrounded with PNe models with different metallicities (Z = Z GD , Z GD /3, Z GD /10) suggest that such a diagram is not well suited to study and compare expansion properties of bright PNe in different environments since all tracks cover or embrace the observational data with no obvious trend with metal content.…”

Section: Expansion Propertiesmentioning

confidence: 99%

“…37 we have to consider that all Galactic bulge objects are to some extent spatially resolved. The typical coverage of the slit is between 30% Richer et al 2008Richer et al , 2009Richer et al , 2010a, and assuming that the halfwidth velocities of Hβ and Hα are the same. Only objects with 5007 Å line strengths greater than Hβ are considered.…”

Section: Expansion Propertiesmentioning

confidence: 99%

“…Spectroscopy done by Górny et al (2004) revealed that the sample of bulge PNe used by Richer et al (2009Richer et al ( , 2010a contains several objects with WC central stars, which are marked in Fig. 37 by crossed symbols.…”

Section: Expansion Propertiesmentioning

confidence: 99%

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The evolution of planetary nebulae

Schönberner

Jacob

Sandín

et al. 2010

A&A

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Aims. By means of hydrodynamical models we do the first investigations of how the properties of planetary nebulae are affected by their metal content and what can be learned from spatially unresolved spectrograms of planetary nebulae in distant stellar systems. Methods. We computed a new series of 1D radiation-hydrodynamics planetary nebulae model sequences with central stars of 0.595 M surrounded by initial envelope structures that differ only by their metal content. At selected phases along the evolutionary path, the hydrodynamic terms were switched off, allowing the models to relax for fixed radial structure and radiation field into their equilibrium state with respect to energy and ionisation. The analyses of the line spectra emitted from both the dynamical and static models enabled us to systematically study the influence of hydrodynamics as a function of metallicity and evolution. We also recomputed selected sequences already used in previous publications, but now with different metal abundances. These sequences were used to study the expansion properties of planetary nebulae close to the bright cut-off of the planetary nebula luminosity function. Results. Our simulations show that the metal content strongly influences the expansion of planetary nebulae: the lower the metal content, the weaker the pressure of the stellar wind bubble, but the faster the expansion of the outer shell because of the higher electron temperature. This is in variance with the predictions of the interacting-stellar-winds model (or its variants) according to which only the central-star wind is thought to be responsible for driving the expansion of a planetary nebula. Metal-poor objects around slowly evolving central stars become very dilute and are prone to depart from thermal equilibrium because then adiabatic expansion contributes to gas cooling. We find indications that photoheating and line cooling are not fully balanced in the evolved planetary nebulae of the Galactic halo. Expansion rates based on widths of volume-integrated line profiles computed from our radiation-hydrodynamics models compare very well with observations of distant stellar system. Objects close to the bright cut-off of the planetary nebula luminosity function consist of rather massive central stars (>0.6 M ) with optically thick (or nearly thick) nebular shells. The halfwidth-half-maximum velocity during this bright phase is virtually independent of metallicity, as observed, but somewhat depends on the final AGB-wind parameters. Conclusions. The observed expansion properties of planetary nebulae in distant stellar systems with different metallicities are explained very well by our 1D radiation-hydrodynamics models. This result demonstrates convincingly that the formation and acceleration of a planetary nebula occurs mainly because of ionisation and heating of the circumstellar matter by the stellar radiation field, and that the pressure exerted by the shocked stellar wind is less important. Determinations of nebular abundances by means of photoionisa...

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Section: Expansion Propertiessupporting

confidence: 43%

Section: Expansion Propertiesmentioning

confidence: 97%

Section: Expansion Propertiesmentioning

confidence: 99%

Section: Expansion Propertiesmentioning

confidence: 99%

Section: Expansion Propertiesmentioning

confidence: 99%

See 3 more Smart Citations

The evolution of planetary nebulae

Schönberner

Jacob

Sandín

et al. 2010

A&A

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A hydrodynamical study of multiple‐shell planetary nebulae

et al. 2014

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We present the result of a study on the expansion properties and internal kinematics of round/elliptical planetary nebulae of the Milky Way disk, the halo, and of the globular cluster M 15. The purpose of this study is to considerably enlarge the small sample of nebulae with precisely determined expansion properties (Schönberner et al. 2005b). To this aim, we selected a representative sample of objects with different evolutionary stages and metallicities and conducted highresolutionéchelle spectroscopy. In most cases we succeeded in detecting the weak signals from the outer nebular shell which are attached to the main line emission from the bright nebular rim. Next to the measurement of the motion of the rim gas by decomposition of the main line components into Gaussians, we were able to measure separately, for most objects for the first time, the gas velocity immediately behind the leading shock of the shell, i.e. the post-shock velocity. We more than doubled the number of objects for which the velocities of both rim and shell are known and confirm that the overall expansion of planetary nebulae is accelerating with time. There are, however, differences between the expansion behaviour of the shell and the rim: The post-shock velocity is starting at values as low as around 20 km s −1 for the youngest nebulae, just above the AGB wind velocity of ∼ 10-15 km s −1 , and is reaching values of about 40 km s −1 for the nebulae around hotter central stars. Contrarily, the rim matter is at first decelerated below the typical AGB-wind velocity and remains at about 5-10 km s −1 for a while until finally a typical flow velocity of up to 30 km s −1 is reached. This observed distinct velocity evolution of both rim and shell is explained by radiation-hydrodynamics simulations, at least qualitatively: It is due to the ever changing stellar radiation field and wind-wind interaction together with the varying density profile ahead of the leading shock during the progress of evolution. The wind-wind interaction works on the rim dynamics while the radiation field and upstream density gradient is responsible for the shell dynamics. Because of these time-dependent boundary conditions, a planetary nebula will never evolve into a simple self-similar expansion. Also the metal-poor objects behave as theory predicts: The post-shock velocities are higher and the rim flow velocities are equal or even lower compared to disk objects at similar evolutionary stage. The old nebula around low-luminosity central stars contained in our sample expand still fast and are dominated by reionisation. We detected, for the first time, in some objects an asymmetric expansion behaviour: The relative expansions between rim and shell appear to be different for the receding and approaching parts of the nebular envelope.

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Planetary nebula populations and kinematics

Richer

2011

Proc. IAU

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Abstract. The brightest planetary nebulae achieve similar maximum luminosities, have similar ratios of chemcial abundances, and apparently share similar kinematics in all galaxies. These similarities, however, are not necessarily expected theoretically and appear to hide important evolutionary differences. As predicted theoretically, metallicity appears to affect nebular kinematics, if subtly, and there is a clear variation with evolutionary stage. To the extent that it can be investigated, the internal kinematics for galactic and extragalactic planetary nebulae are similar. The extragalactic planetary nebulae for which kinematic data exist, though, probably pertain to a small range of progenitor masses, so there may still be much left to learn, particularly concerning the kinematics of planetary nebulae that descend from the more massive progenitors.

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The Evolution of the Kinematics of Nebular Shells in Planetary Nebulae in the Milky Way Bulge

Cited by 25 publications

References 52 publications

The evolution of planetary nebulae

The evolution of planetary nebulae

A hydrodynamical study of multiple‐shell planetary nebulae

Planetary nebula populations and kinematics

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