Search Publications
The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition
Hamann, W. -R.; Todt, H.; Gräfener, G. +1 more
A considerable fraction of the central stars of planetary nebulæ (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type [WC]. We perform a spectral analysis of CSPN PB …
Physical properties of the ESA Rosetta target asteroid (21) Lutetia. II. Shape and flyby geometry
Colas, F.; Fornasier, S.; Carry, B. +22 more
Aims: We determine the physical properties (spin state and shape) of asteroid (21) Lutetia, target of the International Rosetta Mission of the European Space Agency, to help in preparing for observations during the flyby on 2010 July 10 by predicting the orientation of Lutetia as seen from Rosetta.
Methods: We use our novel KOALA inversi…
Multi-wavelength observations of H 2356-309
Klochkov, D.; Santangelo, A.; Quirrenbach, A. +184 more
Aims: The properties of the broad-band emission from the high-frequency peaked BL Lac H 2356-309 (z = 0.165) are investigated.
Methods: Very high energy (VHE; E > 100 GeV) observations of H 2356-309 were performed with the High Energy Stereoscopic System (HESS) from 2004 through 2007. Simultaneous optical/UV and X-ray observations wer…
Resolving the cold debris disc around a planet-hosting star . PACS photometric imaging observations of q1 Eridani (HD 10647, HR 506)
Heras, A. M.; Olofsson, G.; Krivov, A. V. +32 more
Context. About two dozen exo-solar debris systems have been spatially resolved. These debris discs commonly display a variety of structural features such as clumps, rings, belts, excentric distributions and spiral patterns. In most cases, these features are believed to be formed, shaped and maintained by the dynamical influence of planets orbiting…
Magnetic structures of an emerging flux region in the solar photosphere and chromosphere
Solanki, S. K.; Lagg, A.; Xu, Z.
Aims: We investigate the vector magnetic field and Doppler velocity in the photosphere and upper chromosphere of a young emerging flux region of the sun close to disk center.
Methods: Spectropolarimetric scans of a young active region made using the second generation Tenerife Infrared Polarimeter (TIP II) on the German Vacuum Tower Teles…
Transiting exoplanets from the CoRoT space mission . XIII. CoRoT-13b: a dense hot Jupiter in transit around a star with solar metallicity and super-solar lithium content
Mazeh, T.; Aigrain, S.; Alonso, R. +45 more
We announce the discovery of the transiting planet CoRoT-13b. Ground-based follow-up in CFHT and IAC80 confirmed CoRoT's observations. The mass of the planet was measured with the HARPS spectrograph and the properties of the host star were obtained analyzing HIRES spectra from the Keck telescope. It is a hot Jupiter-like planet with an orbital per…
The Herschel Virgo Cluster Survey . VI. The far-infrared view of M 87
Böhringer, H.; Bomans, D. J.; Bianchi, S. +29 more
The origin of the far-infrared emission from the nearby radio galaxy M 87 remains a matter of debate. Some studies find evidence of a far-infrared excess due to thermal dust emission, whereas others propose that the far-infrared emission can be explained by synchrotron emission without the need for an additional dust emission component. We present…
Herschel-PACS imaging of protostars in the HH 1-2 outflow complex
Maret, S.; Henning, T.; Manoj, P. +22 more
We present 70 and 160 µm Herschel science demonstration images of a field in the Orion A molecular cloud that contains the prototypical Herbig-Haro objects HH 1 and 2, obtained with the Photodetector Array Camera and Spectrometer (PACS). These observations demonstrate Herschel's unprecedented ability to study the rich population of protostar…
Water vapor toward starless cores: The Herschel view
de Graauw, Th.; Liseau, R.; Braine, J. +63 more
Aims: Previous studies by the satellites SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7 × 10-9). We investigate the chemistry of water vapor in starless cores beyond the previous upper limits using the highly improved angular resolution and sensitivity of Hers…
The Herschel Virgo Cluster Survey. V. Star-forming dwarf galaxies - dust in metal-poor environments
Bomans, D. J.; Bianchi, S.; Fritz, J. +27 more
We present the dust properties of a small sample of Virgo cluster dwarf galaxies drawn from the science demonstration phase data set of the Herschel Virgo Cluster Survey. These galaxies have low metallicities (7.8 < 12 + log(O/H) < 8.3) and star-formation rates ≲10-1 M⊙ yr-1. We measure the spectral energy di…