Search Publications
Constraining the structure of the planet-forming region in the disk of the Herbig Be star HD 100546
Pinte, C.; Ménard, F.; Weigelt, G. +8 more
Context. Studying the physical conditions in circumstellar disks is a crucial step toward understanding planet formation and disk evolution. Of particular interest is the case of HD 100546, a Herbig Be star that presents a gap within the first 13 AU of its protoplanetary disk, a gap that may originate in the dynamical interactions of a forming pla…
Discovery of close binary central stars in the planetary nebulae NGC 6326 and NGC 6778
Corradi, R. L. M.; Santander-García, M.; Boffin, H. M. J. +3 more
We present observations proving the close binary nature of the central stars belonging to the planetary nebulae (PNe) NGC 6326 and NGC 6778. Photometric monitoring reveals irradiated lightcurves with orbital periods of 0.372 and 0.1534 days, respectively, constituting firm evidence that they passed through a common-envelope (CE) phase. Unlike most…
Planck early results. XIV. ERCSC validation and extreme radio sources
Kneissl, R.; Miville-Deschênes, M. -A.; Bernard, J. -P. +215 more
Planck's all-sky surveys at 30-857 GHz provide an unprecedented opportunity to follow the radio spectra of a large sample of extragalactic sources to frequencies 2-20 times higher than allowed by past, large-area, ground-based surveys. We combine the results of the Planck Early Release Compact Source Catalog (ERCSC) with quasi-simultaneous ground-…
Damped large amplitude transverse oscillations in an EUV solar prominence, triggered by large-scale transient coronal waves
Foullon, C.; Nakariakov, V. M.; Verwichte, E. +1 more
Aims: We investigate two successive trains of large amplitude transverse oscillations in an arched EUV prominence, observed with SoHO/EIT on the north-east solar limb on 30 July 2005. The oscillatory trains are triggered by two large scale coronal waves, associated with an X-class and a C-class flare occurring in the same remote active region…
The Herschel Virgo Cluster Survey. IX. Dust-to-gas mass ratio and metallicity gradients in four Virgo spiral galaxies
Bianchi, S.; Smith, M.; Fritz, J. +20 more
Context. Using Herschel data from the open time key project the Herschel Virgo Cluster Survey (HeViCS), we investigated the relationship between the metallicity gradients expressed by metal abundances in the gas phase as traced by the chemical composition of HII regions, and in the solid phase, as traced by the dust-to-gas mass ratio.
Aims: W…
Inferring the magnetic field vector in the quiet Sun. I. Photon noise and selection criteria
Borrero, J. M.; Kobel, P.
In the past, spectropolarimetric data from Hinode/SP were employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors found predominantly horizontal magnetic fields, others favor an isotropic distribution. We investigate whether it is actually possible to accurately retrieve the magnetic field vector in reg…
Concurrent X-ray, near-infrared, sub-millimeter, and GeV gamma-ray observations of Sagittarius A*
Genzel, R.; Rouan, D.; Ponti, G. +13 more
Aims: The radiative counterpart of the supermassive black hole at the Galactic center (GC), Sgr A⋆, is subject to frequent flares that are visible simultaneously in X-rays and the near-infrared (NIR). Often, enhanced radio variability from centimeter to sub-millimeter wavelengths is observed to follow these X-ray/NIR eruptions. We …
The upper atmosphere of the exoplanet HD 209458 b revealed by the sodium D lines. Temperature-pressure profile, ionization layer, and thermosphere
Moutou, C.; Ehrenreich, D.; Ferlet, R. +6 more
A complete reassessment of the Hubble Space Telescope (HST) observations of the transits of the extrasolar planet HD 209458 b has provided a transmission spectrum of the atmosphere over a wide range of wavelengths. Analysis of the NaI absorption line profile has already shown that the sodium abundance has to drop by at least a factor of ten above …
Detection of CH+ emission from the disc around HD 100546
Pinte, C.; Ménard, F.; Woitke, P. +13 more
Despite its importance in the thermal balance of the gas and in the determination of primeval planetary atmospheres, the chemistry in protoplanetary discs remains poorly constrained with only a handful of detected species. We observed the emission from the disc around the Herbig Be star
Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model
Krivova, N. A.; Solanki, S.; Harder, J. W. +2 more
Aims: We investigate how well modeled solar irradiances agree with measurements from the SORCE satellite, both for total solar irradiance and broken down into spectral regions on timescales of several years.
Methods: We use the SATIRE model and compare modeled total solar irradiance (TSI) with TSI measurements over the period 25 February…