41234
2011
2019
eng
2
563
postprint
1
2019-01-31
2019-01-31
--
Ablation and wind mass-loading in the born-again planetary nebula A 30
We present XMM-Newton and Chandra observations of the born-again planetary nebula A 30. These X-ray observations reveal a bright unresolved source at the position of the central star whose X-ray luminosity exceeds by far the model expectations for photospheric emission and for shocks within the stellar wind. We suggest that a “born-again hot bubble” may be responsible for this X-ray emission. Diffuse X-ray emission associated with the petal-like features and one of the H-poor knots seen in the optical is also found. The weakened emission of carbon lines in the spectrum of the diffuse emission can be interpreted as the dilution of stellar wind by mass-loading or as the detection of material ejected during a very late thermal pulse.
Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
10.25932/publishup-41234
urn:nbn:de:kobv:517-opus4-412341
1866-8372
online registration
Proceedings of the International Astronomical Union 283 (2011), pp. 378–379 DOI 10.1017/S1743921312011519
Keine öffentliche Lizenz: Unter Urheberrechtsschutz
Martín A. Guerrero
You-Hua Chu
Wolf-Rainer Hamann
Lida M. Oskinova
Detlef Schönberner
Helge Tobias Todt
Matthias Steffen
Nieves Ruiz
Robert A. Gruendl
William P. Blair
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
563
eng
uncontrolled
planetary nebulae: individual (A 30)
eng
uncontrolled
X-rays: ISM
Astronomie und zugeordnete Wissenschaften
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Referiert
Open Access
Cambridge University Press (CUP)
Universität Potsdam
https://publishup.uni-potsdam.de/files/41234/pmnr563.pdf
41377
2011
2018
eng
2
postprint
1
2018-07-24
2018-07-24
--
Weak emission line central stars of planetary nebulae
To understand the evolution and morphology of planetary nebulae, a detailed knowledge of their central stars is required. Central stars that exhibit emission lines in their spectra, indicating stellar mass-loss allow to study the evolution of planetary nebulae in action. Emission line central stars constitute about 10 % of all central stars. Half of them are practically hydrogen-free Wolf-Rayet type central stars of the carbon sequence, [WC], that show strong emission lines of carbon and oxygen in their spectra. In this contribution we address the weak emission-lines central stars (wels). These stars are poorly analyzed and their hydrogen content is mostly unknown. We obtained optical spectra, that include the important Balmer lines of hydrogen, for four weak emission line central stars. We present the results of our analysis, provide spectral classification and discuss possible explanations for their formation and evolution.
Planetary Nebulae: an Eye to the Future
urn:nbn:de:kobv:517-opus4-413775
online registration
Planetary Nebulae: An Eye to the Future, Proceedings IAU Symposium 283 (2011) ; DOI: 10.1017/S1743921312012173
Keine öffentliche Lizenz: Unter Urheberrechtsschutz
Helge Tobias Todt
Miriam Peña
Julia Zühlke
Lida M. Oskinova
Wolf-Rainer Hamann
Götz Gräfener
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
462
eng
uncontrolled
stars: AGB and post-AGB
eng
uncontrolled
stars: Wolf-Rayet
eng
uncontrolled
stars: abundances
Astronomie und zugeordnete Wissenschaften
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Institut für Physik und Astronomie
Referiert
Open Access
Cambridge University Press (CUP)
Universität Potsdam
https://publishup.uni-potsdam.de/files/41377/pmnr_462.online.pdf
41370
2011
2011
eng
494
495
2
582
postprint
1
2019-02-07
2019-02-07
--
The role of heat conduction to the formation of [WC]-type planetary nebulae
X-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 repro-duce 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.
Proceedings of the International Astronomical Union
urn:nbn:de:kobv:517-opus4-413702
10.25932/publishup-41370
1866-8372
online registration
Proceedings of the International Astronomical Union 7 (2011) 2, Symposium No. 283 (Planetary Nebulae an Eye to the Future), pp. 494–495 DOI 10.1017/S1743921312012094
false
true
Keine öffentliche Lizenz: Unter Urheberrechtsschutz
Christer Sandin
Matthias Steffen
Ralf Jacob
Detlef Schönberner
Ute Rühling
Wolf-Rainer Hamann
Helge Tobias Todt
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
582
eng
uncontrolled
conduction
eng
uncontrolled
hydrodynamics
eng
uncontrolled
planetary nebulae: general
Astronomie und zugeordnete Wissenschaften
open_access
Mathematisch-Naturwissenschaftliche Fakultät
Referiert
Open Access
Cambridge University Press (CUP)
Universität Potsdam
https://publishup.uni-potsdam.de/files/41370/pmnr582.pdf