@inproceedings{KuehlingMaerkerZehe2006,
author = {K{\"u}hling, Matthias and M{\"a}rker, Michael and Zehe, Erwin},
title = {Musterdynamik und Fernerkundung in der D{\"o}beritzer Heide : [Poster]},
editor = {Gzik, Axel and Hochschild, Volker and Schneider, Ingo and Schr{\"o}der, Boris},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7277},
year = {2006},
abstract = {Mit der politischen Wende in den Staaten des ehemaligen Ostblockes wurde f{\"u}r viele milit{\"a}risch genutzte Fl{\"a}chen ein tiefgreifender Nutzungswandel eingeleitet. Truppen{\"u}bungspl{\"a}tze als stark gest{\"o}rte Bestandteile unserer Kulturlandschaft weisen auf großen Fl{\"a}chen naturschutzfachlich wertvolle Habitatmosaike mit speziellen Lebensgemeinschaften auf. Der Nutzungswandel ist mit einer Ver{\"a}nderung der Vegetationsstrukturen (Sukzession) und weiteren landschafts{\"o}kologischen Prozessen verbunden. Der ehemalige Truppen{\"u}bungsplatz D{\"o}beritz im Norden der Landeshauptstadt Potsdam kann auf eine lange milit{\"a}rische Nutzungsgeschichte verweisen (erste Man{\"o}ver des Soldatenk{\"o}nigs im Jahr 1713). Nach 1992 wurden das NSG D{\"o}beritzer Heide (3.415 ha) und das NSG Ferbitzer Bruch (1.155 ha) ausgewiesen. Als Schutzgebiete nach der Vogelschutzrichtlinie sind sie Bestandteile des koh{\"a}renten Schutzgebietssystems Natura 2000 der europ{\"a}ischen Gemeinschaft. Trotz des Schutzstatus und der milit{\"a}rischen Altlasten unterliegt das Gebiet als gr{\"o}ßte zusammenh{\"a}ngende Naturfl{\"a}che im engeren Verflechtungsraum des Landes Brandenburg einem hohen Nutzungsdruck.
Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006},
language = {de}
}
@inproceedings{MaerkerSchroederEsselbachCapolongoetal.2006,
author = {M{\"a}rker, Michael and Schr{\"o}der-Esselbach, Boris and Capolongo, Domenico and Bentivenga, Mario},
title = {Geomorphological and pedological processes in badland areas of Southern Italy and their interaction with Mediterranean vegetation},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7288},
year = {2006},
abstract = {Interdisziplin{\"a}res Zentrum f{\"u}r Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006},
language = {en}
}
@misc{KochLaschewskyRingsdorfetal.1986,
author = {Koch, Horst and Laschewsky, Andr{\´e} and Ringsdorf, Helmut and Teng, Kang},
title = {Photodimerization and photopolymerization of amphiphilic cinnamic acid derivatives in oriented monolayers, vesicles and solution},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17111},
year = {1986},
abstract = {Cinnamic acid moieties were incorporated into amphiphilic compounds containing one and two alkyl chains. These lipid-like compounds with photoreactive units undergo self-organization to form monolayers at the gas-water interface and bilayer structures (vesicles) in aqueous solutions. The photoreaction of the cinnamic acid moiety induced by 254 nm UV light was investigated in the crystalline state, in monolayers, in vesicles and in solution in organic solvents. The single-chain amphiphiles undergo dimerization to yield photoproducts with twice the molecular weight of the corresponding monomers in organized systems. The photoreaction of amphiphiles containing two cinnamic acid groups occurs via two mechanisms: The intramolecular dimerization produces bicycles, with retention of the molecular weight of the corresponding monomer. The intermolecular reaction leads to oligomeric and polymeric photoproducts. In contrast to the single-chain amphiphiles, photodimerization processes of lipoids containing two cinnamic acid moieties also occur in solution in organic solvents.},
language = {en}
}
@misc{AlbrechtCummingKreuderetal.1986,
author = {Albrecht, O. and Cumming, W. and Kreuder, W. and Laschewsky, Andr{\´e} and Ringsdorf, Helmut},
title = {Monolayers of rod-shaped and disc-shaped liquid crystalline compounds at the air-water interface},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17124},
year = {1986},
abstract = {Calamitic (rod-shaped) and discotic (disc-shaped) thermotropic liquid crystalline (LC) compounds were spread at the air-water interface, and their ability to form monolayers was studied. The calamitic LCs investigated were found to form monolayers which behave analogously to conventional amphiphiles such as fatty acids. The spreading of the discotic LCs produced monolayers as well, but with a behaviour different from classical amphiphiles. The areas occupied per molecule are too small to allow the contact of all hydrophilic groups with the water surface and the packing of all hydrophobic chains. Various molecular arrangements of the discotics at the water surface to fit the spreading data are discussed.},
language = {en}
}
@misc{Neuneck2006,
author = {Neuneck, G{\"o}tz},
title = {Von blinden, weißen und anderen Flecken : Geheimdienste und ABC-Waffen},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-22183},
year = {2006},
abstract = {Gastkommentar von Dr. G{\"o}tz Neuneck, Leiter des Arbeitsbereichs „Interdisziplin{\"a}re Forschungsgruppe f{\"u}r Abr{\"u}stung und R{\"u}stungskontrolle" (IFAR), Institut f{\"u}r Friedensforschung und Sicherheitspolitik, Universit{\"a}t Hamburg.},
language = {de}
}
@inproceedings{Hirschi2007,
author = {Hirschi, Raphael},
title = {The impact of reduced mass loss rates on the evolution of massive stars},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17616},
year = {2007},
abstract = {Mass loss is a very important aspect of the life of massive stars. After briefly reviewing its importance, we discuss the impact of the recently proposed downward revision of mass loss rates due to clumping (difficulty to form Wolf-Rayet stars and production of critically rotating stars). Although a small reduction might be allowed, large reduction factors around ten are disfavoured. We then discuss the possibility of significant mass loss at very low metallicity due to stars reaching break-up velocities and especially due to the metal enrichment of the surface of the star via rotational and convective mixing. This significant mass loss may help the first very massive stars avoid the fate of pair-creation supernova, the chemical signature of which is not observed in extremely metal poor stars. The chemical composition of the very low metallicity winds is very similar to that of the most metal poor star known to date, HE1327-2326 and offer an interesting explanation for the origin of the metals in this star. We also discuss the importance of mass loss in the context of long and soft gamma-ray bursts and pair-creation supernovae. Finally, we would like to stress that mass loss in cooler parts of the HR-diagram (luminous blue variable and yellow and red supergiant stages) are much more uncertain than in the hot part. More work needs to be done in these areas to better constrain the evolution of the most massive stars.},
language = {en}
}
@inproceedings{FullertonMassaPrinja2007,
author = {Fullerton, A. W. and Massa, D. L. and Prinja, R. K.},
title = {Revised mass-loss rates for O stars from the Pv resonance line},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17647},
year = {2007},
abstract = {The P v λλ1118, 1128 resonance doublet is an extraordinarily useful diagnostic of O-star winds, because it bypasses the traditional problems associated with determining mass-loss rates from UV resonance lines. We discuss critically the assumptions and uncertainties involved with using P v to diagnose mass-loss rates, and conclude that the large discrepancies between massloss rates determined from P v and the rates determined from "density squared" emission processes pose a significant challenge to the "standard model" of hot-star winds. The disparate measurements can be reconciled if the winds of O-type stars are strongly clumped on small spatial scales, which in turn implies that mass-loss rates based on Hα or radio emission are too large by up to an order of magnitude.},
language = {en}
}
@inproceedings{BouretLanzHillieretal.2007,
author = {Bouret, J.-C. and Lanz, T. and Hillier, D. J. and Foellmi, C.},
title = {Clumping in O-type Supergiants},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17662},
year = {2007},
abstract = {We have analyzed the spectra of seven Galactic O4 supergiants, with the NLTE wind code CMFGEN. For all stars, we have found that clumped wind models match well lines from different species spanning a wavelength range from FUV to optical, and remain consistent with Hα data. We have achieved an excellent match of the P V λλ1118, 1128 resonance doublet and N IV λ1718, as well as He II λ4686 suggesting that our physical description of clumping is adequate. We find very small volume filling factors and that clumping starts deep in the wind, near the sonic point. The most crucial consequence of our analysis is that the mass loss rates of O stars need to be revised downward significantly, by a factor of 3 and more compared to those obtained from smooth-wind models.},
language = {en}
}
@inproceedings{Gull2007,
author = {Gull, T. R.},
title = {Eta Carinae viewed from different vantages},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18200},
year = {2007},
abstract = {The spatially-resolved winds of the massive binary, Eta Carinae, extend an arcsecond on the sky, well beyond the 10 to 20 milliarcsecond binary orbital dimension. Stellar wind line profiles, observed at very different angular resolutions of VLTI/AMBER, HST/STIS and VLT/UVES, provide spatial information on the extended wind interaction structure as it changes with orbital phase. These same wind lines, observable in the starlight scattered off the foreground lobe of the dusty Homunculus, provide time-variant line profiles viewed from significantly different angles. Comparisons of direct and scattered wind profiles observed in the same epoch and at different orbital phases provide insight on the extended wind structure and promise the potential for three-dimensional imaging of the outer wind structures. Massive, long-lasting clumps, including the nebularWeigelt blobs, originated during the two historical ejection events. Wind interactions with these clumps are quite noticeable in spatially-resolved spectroscopy. As the 2009.0 minimum approaches, analysis of existing spectra and 3-D modeling are providing bases for key observations to gain further understanding of this complex massive binary.},
language = {en}
}
@inproceedings{Reimer2007,
author = {Reimer, A.},
title = {Clumping effects on non-thermal particle spectra in massive star systems},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18246},
year = {2007},
abstract = {Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are also considered as candidate sites for non-thermal high-energy photon production up to gamma-ray energies. The present work considers the effects of wind clumpiness expected on the emitting relativistic particle spectrum in colliding wind systems, built up from the pool of thermal wind particles through diffusive particle acceleration, and taking into account inverse Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy wind causes flux variations of the emitting particle spectrum when the clump enters the wind collision region. It is found that the spectral features associated with this variability moves temporally from low to high energy bands with the time shift between any two spectral bands being dependent on clump size, filling factor, and the energy-dependence of particle energy gains and losses.},
language = {en}
}
@inproceedings{SchnurrCrowther2007,
author = {Schnurr, O. and Crowther, P. A.},
title = {Mid-IR observations of WC stars, and the connection to wind clumping},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17884},
year = {2007},
abstract = {We present preliminary results of a tailored atmosphere analysis of six Galactic WC stars using UV, optical, and mid-infrared Spitzer IRS data. With these data, we are able to sample regions from 10 to 10³ stellar radii, thus to determine wind clumping in different parts of the wind. Ultimately, derived wind parameters will be used to accuratelymeasure neon abundances, and to so test predicted nuclear-reaction rates.},
language = {en}
}
@inproceedings{VinkBenagliaDaviesetal.2007,
author = {Vink, J. S. and Benaglia, P. and Davies, B. and de Koter, A. and Oudmaijer, R. D.},
title = {Advances in mass-loss predictions},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17948},
year = {2007},
abstract = {We present the results of Monte Carlo mass-loss predictions for massive stars covering a wide range of stellar parameters. We critically test our predictions against a range of observed massloss rates - in light of the recent discussions on wind clumping. We also present a model to compute the clumping-induced polarimetric variability of hot stars and we compare this with observations of Luminous Blue Variables, for which polarimetric variability is larger than for O and Wolf-Rayet stars. Luminous Blue Variables comprise an ideal testbed for studies of wind clumping and wind geometry, as well as for wind strength calculations, and we propose they may be direct supernova progenitors.},
language = {en}
}
@inproceedings{MoffatHillierHamannetal.2007,
author = {Moffat, Anthony F. J. and Hillier, D. J. and Hamann, Wolf-Rainer and Owocki, S. P.},
title = {General Discussion},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17953},
year = {2007},
abstract = {Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007},
language = {en}
}
@inproceedings{Sonneborn2007,
author = {Sonneborn, G.},
title = {Imaging and spectroscopy with the James Webb Space Telescope},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17983},
year = {2007},
abstract = {The James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope scheduled for launch in 2013. JWST will find the first stars and galaxies that formed in the early universe, connecting the Big Bang to our own Milky Way galaxy. JWST will peer through dusty clouds to see stars forming planetary systems, connecting the MilkyWay to our own Solar System. JWST's instruments are designed to work primarily in the infrared range of 1 - 28 μm, with some capability in the visible range. JWST will have a large mirror, 6.5 m in diameter, and will be diffraction-limited at 2 μm (0.1 arcsec resolution). JWST will be placed in an L2 orbit about 1.5 million km from the Earth. The instruments will provide imaging, coronography, and multi-object and integral-field spectroscopy across the 1 - 28 μm wavelength range. The breakthrough capabilities of JWST will enable new studies of massive star winds from the Milky Way to the early universe.},
language = {en}
}
@inproceedings{Owocki2007,
author = {Owocki, S. P.},
title = {Dynamical simulation of the "velocity-porosity" reduction in observed strength of stellar wind lines},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17992},
year = {2007},
abstract = {I use dynamical simulations of the line-driven instability to examine the potential role of the resulting flow structure in reducing the observed strength of wind absorption lines. Instead of the porosity length formalism used to model effects on continuum absorption, I suggest reductions in line strength can be better characterized in terms of a velocity clumping factor that is insensitive to spatial scales. Examples of dynamic spectra computed directly from instability simulations do exhibit a net reduction in absorption, but only at a modest 10-20\% level that is well short of the ca. factor 10 required by recent analyses of PV lines.},
language = {en}
}
@inproceedings{Blomme2007,
author = {Blomme, R.},
title = {Corotating Interaction Regions and clumping},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18100},
year = {2007},
abstract = {We present hydrodynamical models for Corotating Interaction Regions, which were used by Lobel (2007) to model the Discrete Absorption Components in HD 64760. We also discuss our failure to model the rotational modulations seen in the same star.},
language = {en}
}
@inproceedings{Kholtygin2007,
author = {Kholtygin, A. F.},
title = {Wavelets for looking for clumping in the wind of OB stars},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17796},
year = {2007},
abstract = {Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007},
language = {en}
}
@inproceedings{UrbanejaKudritzkiPuls2007,
author = {Urbaneja, M. A. and Kudritzki, R.-P. and Puls, Joachim},
title = {Clumping in the winds of O-type CSPNs},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17801},
year = {2007},
abstract = {Recent studies of massive O-type stars present clear evidences of inhomogeneous and clumped winds. O-type (H-rich) central stars of planetary nebulae (CSPNs) are in some ways the low mass-low luminosity analogous of those massive stars. In this contribution, we present preliminary results of our on-going multi-wavelength (FUV, UV and optical) study of the winds of Galactic CSPNs. Particular emphasis will be given to the clumping factors derived by means of optical lines (Hα and Heii 4686) and "classic" FUV (and UV) lines.},
language = {en}
}
@inproceedings{deKoterVinkMuijres2007,
author = {de Koter, A. and Vink, J. S. and Muijres, L.},
title = {Constraints on wind clumping from the empirical mass-loss vs. metallicity relation for early-type stars},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17736},
year = {2007},
abstract = {We present the latest results on the observational dependence of the mass-loss rate in stellar winds of O and early-B stars on the metal content of their atmospheres, and compare these with predictions. Absolute empirical rates for the mass loss of stars brighter than 10\$^{5.2} L_{\odot}\$, based on H\$\alpha\$ and ultraviolet (UV) wind lines, are found to be about a factor of two higher than predictions. If this difference is attributed to inhomogeneities in the wind this would imply that luminous O and early-B stars have clumping factors in their H\$\alpha\$ and UV line forming regime of about a factor of 3--5. The investigated stars cover a metallicity range \$Z\$ from 0.2 to 1 \$Z_{\odot}\$. We find a hint towards smaller clumping factors for lower \$Z\$. The derived clumping factors, however, presuppose that clumping does not impact the predictions of the mass-loss rate. We discuss this assumption and explain how we intend to investigate its validity in more detail.},
language = {en}
}
@inproceedings{ReyesIturbideVelazquezRosado2007,
author = {Reyes-Iturbide, J. and Vel{\´a}zquez, P. and Rosado, M.},
title = {3D numerical model for an asymmetrical superbubble},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-17724},
year = {2007},
abstract = {Massive stars usually form groups such as OB associations. Their fast stellar winds sweep up collectively the surrounding insterstellar medium (ISM) to generate superbubbles. Observations suggest that superbubble evolution on the surrounding ISM can be very irregular. Numerical simulations considering these conditions could help to understand the evolution of these superbubbles and to clarify the dynamics of these objects as well as the difference between observed X-ray luminosities and the predicted ones by the standard model (Weaver et al. 1977).},
language = {en}
}