scholarly journals X-ray, EUV and infrared coronal-line radiation from Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 293-293
Author(s):  
S. A. Zhekov ◽  
M. Perinotto
Keyword(s):  
Thermal Conduction ◽  
Extreme Ultraviolet ◽  
Planetary Nebulae ◽  
Stellar Winds ◽  
Gas Temperature ◽  
Coronal Line ◽  
Temperature Plasma ◽  
Line Radiation ◽  
X Ray ◽  
Central Stars

The interacting stellar winds (ISW) theory (Kwok, S., Purton, C. R., Fitzgerald, P. M., 1978, ApJL, 219, L125) is nowadays widely accepted in the physics of Planetary Nebulae (PNe). It received much support from the observed fast winds in the central stars of PNe (CSPN), recognized to be a quite common phenomenon (e.g., Perinotto, M., 1993, in IAU Symp. No. 155, Planetary Nebulae, eds. R. Weinberger and A. Acker, Kluwer, Dordrecht, 57). Thus, the existance of a hot bubble in the PNe structure is a cornerstone of the ISW model. The high velocities (600–3500 km s–1) of the CSPN winds, are, according to the ISW model, directly responsible for an high gas temperature in the hot bubble, which is then expected to be the source of an extended X-ray and extreme ultraviolet (EUV) radiation. The PNe should also emit infrared coronal lines (IRCL) of highly ionized species since the high temperature plasma of the hot bubble is in contact with the much colder outer shell (optical PN) and the thermal conduction will produce a region of intermediate temperatures (5 × 105–106 K). A model considering the structure of the hot bubble in PNe with taking into account the thermal conductivity effects was present by Zhekov and Perinotto (1996, A&A, 309, 648).

scholarly journals X-ray emission from Planetary Nebulae

1997 ◽  
Vol 180 ◽  
pp. 214-215 ◽  
Author(s):  
Gail M. Conway ◽  
You-Hua Chu
Keyword(s):  
Planetary Nebulae ◽  
Point Sources ◽  
Stellar Winds ◽  
X Rays ◽  
Will Emit ◽  
X Ray ◽  
Extended Sources ◽  
Central Stars

X-ray emission from planetary nebulae (PNe) may originate from two sources: central stars which are 100,000–200,000 K will emit soft X-rays, and shocked fast stellar winds reaching 106–107 K will emit harder X-rays. The former are point sources, while the shocked winds are expected to be extended sources emitting continuously out to the inner wall of the visible nebular shell (Weaver et al. 1977; Wrigge & Wendker 1996).

scholarly journals X-ray Shaping of Planetary Nebulae

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 98
Author(s):  
Martín Guerrero
Keyword(s):  
Stellar Wind ◽  
Essential Role ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Stellar Winds ◽  
Physical Processes ◽  
X Ray ◽  
Hot Gas ◽  
Energy And Momentum ◽  
Central Stars

The stellar winds of the central stars of planetary nebulae play an essential role in the shaping of planetary nebulae. In the interacting stellar winds model, the fast stellar wind injects energy and momentum, which are transferred to the nebular envelope through an X-ray-emitting hot bubble. Together with other physical processes, such as the ionization of the nebular envelope, the asymmetrical mass-loss in the asymptotic giant branch (AGB), and the action of collimated outflows and magnetic fields, the pressurized hot gas determines the expansion and evolution of planetary nebulae. Chandra and XMM-Newton have provided us with detailed information of this hot gas. Here in this talk I will review our current understanding of the effects of the fast stellar wind in the shaping and evolution of planetary nebulae and give some hints of the promising future of this research.

scholarly journals Modeling the diffuse X-ray emission of planetary nebulae with different chemical composition

2011 ◽  
Vol 7 (S283) ◽  
pp. 215-218 ◽  
Author(s):  
Matthias Steffen ◽  
Christer Sandin ◽  
Ralf Jacob ◽  
Detlef Schönberner
Keyword(s):  
Thermal Conduction ◽  
Planetary Nebulae ◽  
Extreme Case ◽  
Circumstellar Matter ◽  
Central Star ◽  
Parameter Study ◽  
Radiation Hydrodynamics ◽  
X Ray ◽  
Model Predictions ◽  
Central Stars

AbstractBased on time-dependent radiation-hydrodynamics simulations of the evolution of Planetary Nebulae (PNe), we have carried out a systematic parameter study to address the non-trivial question of how the diffuse X-ray emission of PNe with closed central cavities is expected to depend on the evolutionary state of the nebula, the mass of the central star, and the metallicity of stellar wind and circumstellar matter. We have also investigated how the model predictions depend on the treatment of thermal conduction at the interface between the central ‘hot bubble’ and the ‘cool’ inner nebula, and compare the results with recent X-ray observations. Our study includes models whose properties resemble the extreme case of PNe with Wolf-Rayet type central stars. Indeed, such models are found to produce the highest X-ray luminosities.

scholarly journals X-ray Shaping of Planetary Nebulae

2018 ◽  
Author(s):  
Martin A Guerrero
Keyword(s):  
Mass Loss ◽  
Stellar Wind ◽  
Essential Role ◽  
Planetary Nebulae ◽  
Stellar Winds ◽  
Physical Processes ◽  
X Ray ◽  
Hot Gas ◽  
Energy And Momentum ◽  
Central Stars

The stellar winds of the central stars of planetary nebulae play an essential role in planetary nebulae shaping. In the interacting stellar winds model, the fast stellar wind injects energy and momentum which are transfered to the nebular envelope through an X-ray-emitting hot bubble. Together with other physical processes, such as the ionization of the nebular envelope, the asymmetrical mass-loss in the AGB, and the action of collimated outflows and magnetic fields, the presurized hot gas determines the expansion and evolution of planetary nebulae. \emph{Chandra} and \emph{XMM-Newton} have provided us with detailed information of this hot gas. Here in this talk I will review our current understanding of the effects of the fast stellar wind in the shaping and evolution of planetary nebulae and give some hints of the promissing future of this research.

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

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.

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

Galaxies ◽  
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.

scholarly journals Hot bubbles of planetary nebulae with hydrogen-deficient winds

2018 ◽  
Vol 620 ◽  
pp. A98 ◽  
Author(s):  
R. Heller ◽  
R. Jacob ◽  
D. Schönberner ◽  
M. Steffen
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Thermal Conduction ◽  
Thermal Structure ◽  
Neutral Hydrogen ◽  
Planetary Nebulae ◽  
Chemical Compositions ◽  
Heat Conducting ◽  
X Ray ◽  
Similar Solutions

Context. The first high-resolution X-ray spectroscopy of a planetary nebula, BD +30° 3639, opened the possibility to study plasma conditions and chemical compositions of X-ray emitting “hot” bubbles of planetary nebulae in much greater detail than before. Aims. We investigate (i) how diagnostic line ratios are influenced by the bubble’s thermal structure and chemical profile, (ii) whether the chemical composition inside the bubble of BD +30° 3639 is consistent with the hydrogen-poor composition of the stellar photosphere and wind, and (iii) whether hydrogen-rich nebular matter has already been added to the bubble of BD +30° 3639 by evaporation. Methods. We applied an analytical, one-dimensional (1D) model for wind-blown bubbles with temperature and density profiles based on self-similar solutions including thermal conduction. We also constructed heat-conduction bubbles with a chemical stratification. The X-ray emission was computed using the well-documented CHIANTI code. These bubble models are used to re-analyse the high-resolution X-ray spectrum from the hot bubble of BD +30° 3639. Results. We found that our 1D heat-conducting bubble models reproduce the observed line ratios much better than plasmas with single electron temperatures. In particular, all the temperature- and abundance-sensitive line ratios are consistent with BD +30° 3639 X-ray observations for (i) an intervening column density of neutral hydrogen, NH = 0.20-0.10+0.05 × 1022cm−2, (ii) a characteristic bubble X-ray temperature of TX = 1.8 ± 0.1 MK together with (iii) a very high neon mass fraction of about 0.05, virtually as high as that of oxygen. For lower values of NH, we cannot exclude the possibility that the hot bubble of BD +30° 3639 contains a small amount of “evaporated” (or mixed) hydrogen-rich nebular matter. Given the possible range of NH, the fraction of evaporated hydrogen-rich matter cannot exceed 3% of the bubble mass. Conclusions. The diffuse X-ray emission from BD +30° 3639 can be well explained by models of wind-blown bubbles with thermal conduction and a chemical composition equal to that of the hydrogen-poor and carbon-, oxygen-, and neon-rich stellar surface.

scholarly journals X-ray Studies of Planetary Nebulae

2016 ◽  
Vol 12 (S323) ◽  
pp. 104-108
Author(s):  
Rodolfo Montez
Keyword(s):  
Mass Transfer ◽  
Planetary Nebulae ◽  
Central Star ◽  
Electromagnetic Spectrum ◽  
Stellar Winds ◽  
X Ray ◽  
New Directions ◽  
Multi Wavelength ◽  
Formation And Evolution ◽  
Compact Sources

AbstractX-ray emission from planetary nebulae (PNe) provides unique insight on the formation and evolution of PNe. Past observations and the ongoing Chandra Planetary Nebulae Survey (ChanPlaNS) provide a consensus on the two types of X-ray emission detected from PNe: extended and compact point-like sources. Extended X-ray emission arises from a shocked “hot bubble” plasma that resides within the nebular shell. Cooler than expected hot bubble plasma temperatures spurred a number of potential solutions with one emerging as the likely dominate process. The origin of X-ray emission from compact sources at the location of the central star is less clear. These sources might arise from one or combinations of the following processes: self-shocking stellar winds, spun-up binary companions, and/or accretion, perhaps from mass transfer, PN fallback, or debris disks. In the discovery phase, X-ray studies of PNe have mainly focused on the origin of the various emission processes. New directions incorporate multi-wavelength observations to study the influence of X-ray emission on the rest of the electromagnetic spectrum.

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